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8 May, 2020

Part-2 Wave Phenomenon, Antennas & Radiation - Magnetism

Part 2: Wave Phenomenon, Antennas & Radiation - Theory and Practice
Electromagnetic (EM) Waves - A few more definitions for the Series

"We are much to accustomed to attribute to a single cause that which is the product of several, and the majority of our controversies come from that."  - Marcus Aurelius (121 - 180 )

Wave propagation is one phenomenon whose end looks like a single product, however in reality is an accumulation of many causes all having a unique contribution to the end product.  Over the centuries man has put together many mathematical and physical test to prove or disprove the cause and effect of the many controversies that have been and still are on the discussion table.

This series will answer some of the controversies and well as add new ones to continue on with the discussions, hopefully move up towards the ultimate knowledge or even better closer to the root basics of knowledge to establish a more solid foundation to grow.

Wave_Index Quick Links

Quick review to set the atmosphere for Part 2:
In Part-1 we discussed the wavelength with respect to frequency and referenced to the speed of light, Lambda=f/cwhich always raise the questions why the speed of light and in that case what is the speed of light?  To start the speed of light is a reference that has been observed in a created vacuum of the time it takes a laser beam to travel one second referenced to a 1 meter distance.  The actual derived number for the speed of light is 2.99792458 108  meters/second.  OK does that number hold true in space?  Again another controversy added to the table.  For the time being if we make this a constant, we will have the ability to change it to a variable later.  We will use this to discuss the Electromagnetic (EM) radiation phenomenon being propagated to better understand some of the parameters that determine distance the EM wave travels before it dissipates in to a non measurable entity with the instrumentation we currently have available to the public.

The frequency allocated spectrum that is compartmentalized into groups of frequencies call bands like the FM Radio BAND of 88MHz-108 MHz have been created over the years until it was realized that a standard band allocation has to be created to maintain some form of communications for growth.  So now we have a mechanism to relate the wavelength to frequency and band.  Any frequency may be represented with an associated wavelength in meters, however a band has to have a width assigned to it as the FM radio band.  The FM band falls inside the VHF band (10m to 1m)  and the actual FM band is (c/88MHz to c/108MHz) meters = 3.44 meters to 2.77 meters.  

In part 1 Introduction we also discussed the Inverse-Square Law of radiant energy from a source (GM) as defined by Equation 1.0 below.  As we see the radiant energy is reduced by the Inverse-Square of the distance from the source.

alt alt  Equation 1.0 Intensity at surface of sphere at Radius R

Authors Note:
Electromagnetic EM wave phenomenon  is the easiest subject to springboard off on a tangent while attempting to get to the root of the subject matter, only to be mentally exhausted and many times end in the same place started.  As the series moves forward we will represent EM waves mathematically only to the pint it becomes applicable to our intent of the series.  Some analysis will require linear algebra, analytical geometry and integral calculus to represent the wave phenomenon.   The objective of this series is to present EM wave phenomenon's interaction with other forces on this planet and the habitants therein.  The place that was selected to start is the planet Earth since our very existence resides on this planet Earth so what better place to start.  Understanding what has been an "experimental" exercise for the past couple of thousand years on our magnetic fields and Earth's magnetic radiation fields only tells us that we need to dig deeper.
Enjoy the series - Sal Tuzzo

What we want to cover in Part 2:
Starting a new blog series for BASIL Networks always means setting a solid foundation of reference for the series to transfer knowledge to our readers.  The intent and expectations for this series is the same for all our series - our blog's are living publications and will be updated and revised as we receive requests and contributions to the series.

The amount of scattered information on the Internet is overwhelming for any subject matter such that one could get lost just looking at content and easily loose focus on the intent of their initial search.  The issue of a infinite information library is not only where to start and more important, what is the expected results one is searching to find.  We will on occasion place a reminder on the expectations of this blog series in order to stay focused, "Author included".  The expectations for this series are to understand "Wave Phenomenon, Antennas and Radiation", the effects of radiated EM waves on materials in the waves path, frequency resonance of propagated waves influence on biological entities with respect to the Earth's radiations system.

Since this is an educational blog the intent is to cover the "boring" foundations from the recorded beginning to where we stand present day on this "Wave Phenomenon, Antennas and Radiation"   There are many physicists world wide discovering new applications as well as the home brew self educated innovators researching this "field" phenomenon which is still an experimental fact without an origin.

Lets Get Started - More Basics:
OK, Part-1 presented a lot of overview information about radiated power, radiation types, the effect radiation has on everything in our environment including humans which has triggered many questions.  We will stay focused, answer all questions, some in detailed if they are part of the presentation for the part being presented.  If the questions fall outside the current presentation we will give a general answer and present the question when the section of the series addresses the question directly.  So with that being said, lets answer some questions.

Questions & Answers
It only took a few days for the questions to come in from Part-1.  Some of the questions are a bit out of the sequence that we want to present, so we will try and keep this from running off to deep space and follow the learning progression to be able to connect all the dots.  All questions will be answered as we enter the sections they pertain to.  At this time we are still in the basic settings for the series.

Q.  What quick example would you give to show radiation exists in our everyday lives may be damaging to us?
A.  The Microwave oven, boiling water is simple and it only takes about minute.  The microwave oven frequency resides in the 2.4 GHz band and our bodies plasma is about 50% water mixed with other viscous structures makes up the delivery highway system to "every organ in the body".  The Microwave modulates the water molecule to absorb the energy causing heat which modifies its molecular structure. Today's WiFi routers also operate at 2.4 GHz band along with other Bluetooth wireless devices such as earphones, cell phones and a lots more.

Setting Basics for the Series
Setting the atmosphere for this series is a challenge since it encompasses several disciplines of engineering technologies and encourages the relationships of these multiple disciplines.  However do not get discouraged, this series will as all of our series incorporates the OBD methodology Overview, Basics, Detailed to walk you through a new experience of an ever changing field of wireless communications.  OK, lets set a Basic foundation of Given Facts that this series will reference, also for those that are very new to wave phenomenon as to set a solid foundation to relate as we move on through the series Youtube has many tutorials at all levels to bring those new to the field up to speed easily.
"If you wish to understand the universe, think of energy, frequency and vibration." - Nikola Tesla.

Immutable and Mutable Universal Laws
There two types of  Universal Laws in the universe,  Immutable and Mutable, Yeh, a ZM (Zen Moment).  That is easy enough right?   Immutable Laws as the definition or the word states are laws that "can not" be changed over time, not subject or unable to be changed, absolute.  You remember growing up and your mom says "NO."Cool   Mutable Laws are laws that are subject to change either completely or slightly and effect our very existence, you know when you talk back to your parents and you get a response " keep it up and you will experience pain".Foot in mouth   OK, now another Zen moment, if the Universe is ever changing then where do Immutable Laws exist in the Universe?  Again another controversy added to the table.  Here on this planet Earth, scientists, mathematician and physicists have empirically derived many constants that we will use in this series only "for convenience".

Convolution Theorem in Mathematics
OK, we are not going to bore you with the long version of the Convolution Theorem, just an overview.  The word convolution according to Merriam-Webster 1. :a form or shape that is folded in curved tortuous windings, 2. : one of the irregular ridges on the surface of the brain and especially of the cerebrum of higher mammals, 3. : a complication or intricacy of form, design, or structure.  OK, that doesn't sound like wave phenomenon; just another word taken from the normal language and transformed into a mathematical definition.

To convolve is to roll together to form another, so when two EM fields convolve they form a different EM field.  Convolution in the mathematics field generally usually relates to the Fourier Transforms of combined waveforms and the Fourier Transform is a way to separate the combined waveform to its singular components or frequencies.  We will use these theorems later in the series.

Brief History of Electric and Magnetic Fields
"We are much to accustomed to attribute to a single cause that which is the product of several, and the majority of our controversies come from that."  - Marcus Aurelius (121 - 180 ).  This quote or paraphrases thereof seam to be around in every class on magnetic "field theory".  The basic foundation of what is understood about magnetism and the magnetic field has many contributors from 600BC to present day and still no "what is its origin" answers even with empirical experimental facts of its stimulus-response observations over 2000 years.

The phenomenon of magnetism is currently explained to be a "field" activated in space or air by the magnet or electrical current.  However, we have no idea what a "field" could be.  It is neither space nor matter; yet, it exists within space, and is affected by, and can affect matter.  Furthermore, what or how and why does the activated "field" take on the unique shapes that it does?

Thales of Miletus - (624/623 – c. 548/545 BC) Greek mathematician, astronomer and Pre-Socratic philosopher.  Thales' theorems in elementary geometry Intercept Theorem are theorems we will use later in the advanced part of the series.  Thales' hypothesized that the operating principle of nature and the nature of matter was a single substance; "water".  His observation in 600 BC was that rubbing a piece of amber will attract straw.  Thales' was also the earliest known researcher into electricity.

Lets look at the time frame when  the "magnetic compass" was first developed in 200 BC and only took a few hundred years to the 11th century to be found useful for navigation.  From there the first recorded navigation usage in Western Europe was around 1190 up to that point the navigational sextant was used.  Things pick up in the 1700's  jumping forward in time six centuries or so.  The advancements continued on with the magnetism phenomenon when in 1785 Charles-Augustin de Coulomb published Coulomb's Law or Coulomb's Inverse-Square Law, the one we used in Part-1.

In 1820 a discovery was made by a Hans Christian Ørsted known as Oersted's Law showing the magnetic properties of an electric current in a wire.  André-Marie Ampère a French physicists and mathematician together in 1819-1820 presented electromagnetism the unity of electric and magnetic phenomenon Ampere's force law and Ampeian Loop Model and the B-Field resulted.  Michael Faraday an English scientist invented the electric motor as well as contributing to the study of electrochemistry, electromagnetic induction, diamagnetism and electrolysis.  We will present electrochemistry properties as the series moves forward to show the effects on the bio-chemistry of living cells.

Also during the 1820's two French physicists and mathematicians with alternative interests in astronomy and the other a violinist interested in vibration bodies, Jean-Baptiste Biot and Félix Savart respectively together discovered the Biot-Savart Law that describes the magnetic field generated by a constant electric current incorporating Amperes' law.  The 1800's was a decade of discovery for science and the field of electromagnetism.  This Biot-Savart Law will be presented in this part to identify the magnetic flux intensity of a point on the Earth empirically.

It is very difficult to pinpoint the actual discovery of the phenomenon, however the people involved that published the experiments and basic laws we incorporate in today's engineering and scientific research empirically represented these obversations mathematically in a way for the research and discussions to move forward. A synopsis of what was taught on science and engineering when all this started way back in the 1800's two centuries past and this magnetic field phenomenon is still being discussed.  We still do not have a suitable explanation of magnetism's  "field" origin or what it is, however we have many experimental facts of what it does and lots of mathematics to represent the experiments.  Ok, there must have been a lot happening from 600BC to 1800's AD and developed separately until the 1800's.  Well that was helpful. Cool  

A lot of stimulus-response experiments have produced several mathematical relationships that are useful in the "Space-Time-Continuum" that actually relate within the "boundaries specified" for their use.

Summary of Electric & Magnetic Fields:
The current definition of  the phenomenon of magnetism is said to be a field activated in space by a magnet or electrical current which, over the past few centuries is an experimental fact only with no idea what a "field" actually is.  It is neither space nor matter;  yet, it exists within space, affected by the space, travels through a conductor and to add to this the "field" affects all matter and also takes the form of peculiar shapes.

All the laws, Coulomb's, Ampere's,  Maxwell's, Orsted's, Faraday's and Biot-Savart all prove each other and just validate the experimental data observed.  There is no explanation of ground zero for a magnetic "field", really? yes really! there is no known scientific explanation of what it is, it just exists everywhere.  Science has represented (not defined) a magnetic field through a series of various analytical forms that represent empirical effects or a "stimulus condition" in the region around a magnet or an electric current, characterized by the existence of a detectable magnetic force at every point in the region and by the existence of magnetic poles.  This is paraphrased from several websites all lead to an experimental fact which explain many applications except the non-physical phenomenon of what it actually is and not just its experimental influence.  It is said that if you repeat a phenomenon three times the point will be understood.

Magnetism and Space
OK, for those that want to study this further beyond the scope of this blog a good place to start is Nikola Tesla and aether and Non-Physical Space.  From the notes of Nikola Tesla, "The day science begins to study non-physical phenomena, it will make more progress in one century than in all the previous centuries of existence."   "There is no energy in matter other than that received from its environment."  So this aether-space thing, has no mass, infinite elasticity, an all pervading medium of propagation of electromagnetic waves that has influence on everything.  This aether medium carrying this Electromagnetic (EM) force will continue until an opposite aether medium EM force in its path interferes with its travel.  Simple, "every action has an opposite and equal reaction", I remember reading that in a physics book somewhere.  So, now that is out of the way, lets get back to the stimulus and response of this EM wave phenomenon.  The thought to keep in mind is the aether is a transport medium for EM waves just like plasma is a transport medium for the human body, just different domains, and an EM wave will travel until it is interfered with another EM wave to either amplify, reduce or change its current effectiveness.

Earth's Magnetic field:
So now that we have a little history of how all this magnetic "field" theory came about lets look at what has been done to understand more about it.  Remembering Coulombs Inverse-Square Law in the previous section there has to be some electricity or charge flowing to produce a magnetic field and the earth supplies that charge from different minerals copper, zinc, carbon and many other ores'  that create some type of galvanic action at the various levels or layers  of the earth cores' in which the Earths Magnetic fields are generated.

OK, the convenience part shown in Figure 2.0a which is a simple sphere magnet resting permanently with its Geometric North and Magnetic North at the same point on the sphere and the flux lines are nice and neat from South to North around the sphere.  OK the not so convenient part is that Earth is not like that. In fact it is at a tilt of 23.5° East from the Geographic North Pole and the Magnetic North is also different from that by at this writing about 2.5° over the past 22 years as well.

Earths Magnetic Field, shown in Figure 2.0b, Physical North is the Magnetic South and the Physical South is the Magnetic North this definition helps the analytical process for clarification and convenience of the experiments that have been processed.  Hence: the experimental fact that unlike poles attract and like poles repel.  Also these layers of molten materials flow inside the cores at different rates depending on the characteristics of each metallurgic characteristics, size, temperature, current position of the planet and a few other parameters like plate shifts, earthquakes, all cause spikes in EM fields throughout the planet, that we will discuss later.

So the earth is a rotating sphere and it should have the same magnetic field as a magnetic sphere right?  Not really for the simple fact that the magnetic sphere is a solid and the earth's core varies in viscosity and density.  Figure 2.0a,b shows the different magnetic fields of a sphere vs Earths measured magnetic fields from the IAGA (International Association of Geomagnetism and Aeronomy) data table measured and recorder every 5 years created collected data is called the International Geomagnetic Reference Field. The (IGRFddd) tables where ddd is the tables reference and are downloadable and plotted to the following Figure 20.1b.  The IGRF2015 Table lines in Figure 2.0b was created from data gathered from orbiting satellites and other geomagnetic instrumentation around the globe.

IMAGE_MagneticField-EarthScale.jpg
Figure 2.0a. Rotating Spheres' Magnetic Field ω = x

alt
Figure 2.0b. Earth's Magnetic Field IGRF Table2015

       Figure 2.0 [a, b]   Rotating Sphere Magnetic Field vs Earth's Magnetic Field

So looking at Figure 2.0b we see that the magnetic fields of the earth are quite different and using deductive reasoning with the understanding that the earth's core is not a fixed stationary solid on a fixed axis, would only stand to reason that the magnetic fields would change according to the earth's motion in order to find its equilibrium.  Also note that the earth is tilted about 23.5 Like riding a bike for the first time and warbling a bit until you get your balance.  By the same deductive reasoning the Earth's magnetic fields would also have several motions or paths of varying frequencies and amplitudes around the planet that makes up these different fields.  The Earth has multiple frequencies of different amplitudes for the very fact that the core is always in a state of continuous movement and is continuously changing density and its core viscosity while spinning on its axis of 1 revolution every 23 hours 56 minutes 4.1 seconds as well as spinning around the sun within our solar system.  Our solar system is also spinning around the galaxy our solar system resides in.  So for the time being lets remain inside the living atmosphere for our species on the Earth.

The experimental data from the surface of the planet globally has been plotted in three graphs, the magnetic radiation intensity, the Inclination and the Declination from the point of reference which is magnetic North.  The magnetic poles that form the Earth's magnetic fields are dipolar that is the poles do not coincide, hence: Physical North is Magnetic South and Physical South is Magnetic North.  The compass needle has two poles north and south, if the compass always points north then the needle that is pointing north is really magnetic north, this is called the horizontal intensity component of the magnetic field.  So the Earth is like a big cement mixer rotating and shifting the core mixing everything up and creating multiple flux lines that also vary as it travels through space linked to our solar system.

The Inclination component of the map shows lines that vary from -90 degrees (up) to +90 degrees (down) where 0 is the equator mark.  The Declination component is the displacement of the true magnetic North from the Geophysical north.  The Declination or the magnetic north shift over time has declined about 2.5° over the past 22 years.  The Declination component is a positive eastward deviation relative to true north represented as an angle relative to magnetic north and true north.

As we stated many physicists and mathematician participated in the empirical experimentation and all have their own references to label the field strength as the Table 2.0 below shows the various field names cross reference;

Value Symbol Parameter To Parameter

  Value

1 SI Gamma Weber/meter2 1.00000000E-004
1 B Gauss Weber/Inch2 6.45160000E-008
1 L/cm2 Line/cemeter2 Weber/centimeter2 1.00000000E-008
1 M/in2 Maxwell/inch2 Tesla 1.55000310E-005
1 M/m2 Maxwell/meter2 Weber/centimeter2 1.00000000E-004
1 T Tesla Maxwell/inch2 6.45160000E+004
1 W/cm2 Weber/centimeter2 Line/cemeter2 1.00000000E+008
1 W/in2 Weber/Inch2 Gauss 1.55000310E+007
1 W/m2 Weber/meter2 Gamma 1.00000000E+009

 Table 2.0  Converting Values and Labels for Convenience

The Intensity of Earth's magnetic fields varies from around 25µT around the equator and around 60µT at the poles, Figures 2.1, 2.2, 2.3 and 2.4 represent the magnetic fields components magnetically, North, South, East, West for a selected point on the planet and shows how the planet core changes in magnetic field intensity.

The Earth's rotation both on its axis and its orbital rotation around the sun influences the random earth quakes and tremors recorded by seismic sensors positioned globally through globe.  Data collected from these sensors are shared through a world scientific collaboration and available to the public for research.  The following data and images are referenced to the National Oceanic and Atmospheric Administration  Center For Environmental Information (NOAA NCEI)  NOAA NCEI.

alt
Figure 2.1  Earth's Magnetic North
2019 Declination
Obtained from NOAA NCEI/CIRES Model

EarthsMagFields-IntensityScale.jpg
 Figure 2.2  Earth's Magnetic Field
Intensity 2020 Map
obtained from NOAA NCEI

alt
Figure 2.3  Earth's Magnetic North
Inclination 2015 Map

obtained from wikipedia

alt
Figure 2.4  Earth's Magnetic Field
Declination 2020 Map

Measuring  Earth's Magnetic Filed's:
OK, now that we have a small overview of the magnetic field phenomenon showing it is all around us in this thing called air space we will now get down to the observations that have been recorded by the physicists and the laws that have been presented.  I know to some that this may be boring, however we will be using this throughout the series when we get into the wireless radiation and its effects.  Yes, learning behavior is so unpredictable and always has been for our species.  Sometimes those that have not been exposed to a field of interest give us some of the most advanced observations that the experts sometimes overlook, it is called being human.  If you got this far reading take a deep breath - we are not going to cover equations like Maxwell's laws etc, that is for the math class to cover and explain, however we will cover the Biot-Savart law (effectively Maxwell' 4th equation) since it is the easier of all the laws and ends up with a simple algebraic equation that we can just plug in the numbers.  The construction of a Tangent Galvanometer is quite simple to assemble and is relatively inexpensive, less than $12.00, we will take pictures in the next part of the series.

Since this is magnetic field phenomenon is still in the experimental arena since a "field" has only been explained as an experimental fact showing these experimental facts via the Earth's magnetic fields we will now incorporate these magnetic law relationships and link the Brief History of Electric and Magnetic Fields in the previous section to a real world application.

Figures 2.0 through 2.4 show the Earth's magnetic field measurement components we will take the walk through how these field maps came about.  Every first year physics student has seen this performed many times in the classroom so, this make for a great example and the Internet is full of video examples all giving their own interpretation of this measurement with equivalent results.  

OK, A galvanometer is basically an ampere meter like Figure 2.5a above that measures current through a wire by displacing a rotating coil needle inside a "fixed" permanent magnet depending on the electromagnetic field the current produces in the coil needled wire.  The Tangent Galvanometer is a device that allows the creation of an electromagnetic field intensity that is equivalent to the magnetic intensity field being measured.  In the previous section the laws set for convenience mathematically move domains from magnetic field and electric current in order to satisfy and prove each others laws, which they do.  So since several physicists-mathematicians introduced different observations,  created laws explaining their observations and they all ended up proving each other's law, it is at this time by experimental fact safe to use them in our analysis here on Earth at least.  One note about the Tangent Galvanometer is that the wire size used for the coil and the number of turns have an influence on the actual intensity of the field.  This is due to the wire resistance and length that will effect the current supplied and the magnetic field produced by the wire and measurements outside the center of the coil will be influenced.

Now that we have an overview of the Earth's Magnetic fields from Figures 2.0 to 2.4 we will walk through the experimental exercise of just how the magnetic field intensity is measured at a point on the Earth.  The Galvanometer and the compass have been around for some time when the Tangent Galvanometer was created to understand more about the magnetic North and the Geographic North pole.  The Tangent Galvanometer measures a point of magnetic intensity tangent to the fields flux line geometry; the point tangent to the flux line has both magnitude and direction which makes it a vector.

alt
Figure 2.5a  D'Arsonval Galvanometer Permanent Magnet
and rotating coil needle movement

alt  
Figure 2.5b  Sine and Tangent Galvanometer
Claude Servais Mathias Pouillet (16 February 1790 – 14 June 1868)

The Tangent Galvanometer was designed by Claude Servais Mathias Pouillet (16 February 1790 – 14 June 1868) and still is in use today by colleges and universities and the industry although the manufacturing is a bit modernized and simplified.  The technology has advanced to the level that a single Integrated  circuit gives all three intensities x, y, and z in Tesla's.

Figure 2.5b  shows the Sine and Tangent Galvanometer made around 1850 in Paris by Ruhmkorff after plans by Claude Pouillet.  It consists of a non-magnetic ring with 10 to 100 turns of wire where a current is placed (I) generating an electromagnetic field (B) to be equivalent to the intensity of the magnetic field B(r) being measured and a compass resting in the middle.  The round hollow part of the device contains a fixed number of turns (N) of a fixed wire size diameter dl in meters and acts as a toroid that generates a magnetic field that is referenced at the center of the toroid.

So, the first step is to represent the different Magnetic components of the Earth. This is shown in Figure 2.6 that represents the magnetic vector components of a single point of the Earth's magnetic field and will be used to mathematically represent the magnetic Intensity.

The Earth's Magnetic Components:
Before we jump too deep lets look at the magnetic components of the planet Earth as shown in Figure 2.6 Earth's Magnetic Field Components as to get a pictorial of the interaction of these vectors.  The process to obtain the magnetic field intensity at a selected point on the Earth using the Tangent Galvanometer such that we are able to calculate the intensity vector r'  shown in Figure 2.6 is simply generating an equivalent magnetic field using the coil in the Tangent Galvanometer that will emulate the geometry of the field at a point tangent to that field, simple.

The Tangent Galvanometer only allows us to obtain the horizontal magnetic field pointing to the Magnetic North at the point of measurement which is the adjacent to the angle of inclination this is the horizontal or parallel component of the Earths magnetic field at the point of measurement.  Since the tangent point contains a magnitude and direction from the point of the measurement this forms a right triangle that contains the angle of inclination as shown in Figure 2.6.  The point of measurement latitude, longitude and inclination angle gives us the magnitude and direction, the hypotenuse of the right triangle r for the point we want to measure.

alt
Figure 2.6  Earth's Magnetic Field Vector Components Summarized

To measure the Earth's magnetic field Intensity at a point lets list the Givens, Measured, Controlled and Finds to setup the process.

Given:

    Latitude, Longitude = Point to be measured
   Area of circle:    alt
   Circumference:   alt 
   alt  Permeability constant

Tangent Galvanometer:
     Coil Size in Meters = 0.16256  (6.4 inches)
     Number of Turns of Coil = 15 Turns
     Wire size = 16 AWG = 0.058" = 1.29 mm

Measure:
    Inclination Angle at Measure Point Lat,Long

Controlled:
     I = Applied Coil current in Ampere's
           Current to move Compass N 45º East

Find:
     alt Magnetic Field of the Horizontal  (Parallel Component)
               generated by the coil current.

    Magnetic Field B at MP (Measurement Point)

Measure:  Inclination Angle alt  for the vector at the point of measurement.

Since we will be creating the horizontal (parallel) magnetic flux component using the tangent galvanometer we will require the Inclination angle that the magnetic field is at.  This is easily obtained using a compass on a flat surface recording a fixed point A degrees then rotating it 90º towards the east an record the angle B the needle moves as shown in Figure 2.7.  The Inclination angle is A+B = Angle in Degrees.  This allows is to calculate the actual magnetic field strength of the point of measurement, we will get to that shortly.

alt

alt

Figure 2.7  Measurement of Angle of Inclination Using A Compass

Step-1
Remove all current from the coil of the Tangent Galvanometer and align the north to be in parallel with the coil as shown in Figure 2.8.  Then place the Tangent Galvanometer at a right angle to the surface and measure the angle of inclination (alt ), record this angle in degrees and return the galvanometer to its upright position and check to see if the compass is still horizontal to the coil as shown in Figure 2. 8.

alt
Figure 2.8  Top View of the Tangent Galvanometer for Step 1

Step-2
Apply a current to the coil that will move the compass needle to 45° (NE)  as shown in Figure 2.9 and record the current applied to the coil.  At this point the Magnetic North is equivalent to the magnetic field we are attempting to measure.  For this experiment we are referencing the point to measure from the center of the wire loop which creates a symmetry that all the current elements contributions around the loop add directly at the center. The current in the loop produces a magnetic force equivalent to the MP at the center of the loop equivalent to the Magnetic North which is used to compute the parallel flux line force that is obviously parallel to the flux line of the point we are measuring at the center of the Galvanometer loop.  The intensity tangent to the flux line is at the inclination parallel to the flux line as shown in Figure 2.10a and the vector is shown in Figure 2.11.

alt
Figure 2.9  Top View of the Tangent Galvanometer for Step 2

Step-3
Record the number of turns setup on the Tangent Galvanometer (N = 15).  The one we will use has a selection of 5, 10, 20 and 35 turns.  We will select the 15 turns connections.

Step-4 
Measure the diameter of the toroid coil of the Tangent Galvanometer in meters (2R = 0.16256 meters (6.4 inches)) for our Tangent Galvanometer we are using a 6.4 inch ABS pipe 3/4 inches long to wrap 16 AWG copper laminated magnet wire 15 turns.

Biot-Savart Law Applied
The Biot-Savart Law is only one of many laws that have been created empirically to show a magnetic energy "field" exists from applying an electric current in some way or another.  We will apply this law to measure the magnetic force for a point on Earth.  This technique is applicable to other magnetic measurements as for a bar magnet, a circular magnet and other forms of magnetic generation.  The law applies when analyzing a magnetic "field" to its Magnitude, Direction, Length and proximity to the source of the energy field.

It is an interesting point of why the Galvanometer wire loop was selected instead of the typical coil, Figure 2.10a and Figure 2.10b show the differences in magnetic fields of a wire loop and a wire coil.  The wire loop allows us to use the Tangent galvanometer to actually measure an unknown field and creates a symmetry since all contributions are added at the center of the wire loop and is the same throughout the loop makes for a unique condition for analysis mathematically using the Biot-Savart Law.  The coil in Figure 2.10b the main magnetic field is in the center of the coil which is normally configured for a solenoid with a magnetic rod in the middle since the majority of the magnetic field is in the center of the coil and has weaker fields outside the coil.  The more turns on this type of configuration the stronger the magnetic field strength will be.

This is not rocket science level however it is important to the series since we will be referencing it when we get into other radiation methodologies created by a current.  Lets look at the magnetic field of a loop of wire as shown below in Figure 2.10a and the vector representation in Figure 2.11 as we see the most intense field is in the center of the coil, as the field expands around the coil the field is weakened until it blends with the Earth's magnetic field and blends in as part of it.  An interesting note is that depending on the wire size and form the magnetic fields will reshape to that form.

alt
Figure 2.10a Magnetic Field Wire Loop

    alt

 

    Figure 2.10b Magnetic Field Wire Coil

Magnetic Fields of the Tangent Galvanometer Wire Loop and a Solenoid Coil

There are three components that influence alt at the Measurement Point (MP) and they are a. I the current in the coil, b. alt the parallel field intensity create by the current in the coil and c.  alt the inclination angle direction of the field we are measuring as shown in Figure 2.10b.  MP the measurement point,  is tangent to the loops magnetic field created from I, the coil current where as altis that magnitude and direction of Earth's Latitude and Longitude given point we want to measure.  The intensity alt orthogonal to the parallel field does not contribute since it is at (90°) and the scalar components point in different directions perpendicular to the axis and the complete loop is 0 due to the symmetry where all field contributions add at the center of the loop this is a unique case in the geometry for the Tangent Galvanometer.  The alt component then becomes the circumference of the wire loop alt.  Only alt contributes to the total intensity B at point MP being along the parallel flux line axis of the loop.  The symmetry created from the current applied to move the compass needle 45° creates the symmetrical magnetic fields that is equivalent to the field point tangent to the current I flux line being measured and the inclination angle alt will give the direction.

alt
Figure 2.11  Vector Representation of the Tangent Galvanometer Wire Loop Setup

So for the different contributions, the Tangent Galvanometer and the current applied to coil produce the equivalent magnetic field strength of the magnetic north (alt ) is given as the Biot-Savart Law as Equation 2.1 below.  The only contribution to obtaining B is integrating alt which is defined as:

alt

The current I contribution to MP to calculate B for the point in question is given when we adjust the current to move the compass 45° NE in Figure 2.11.  This sets the equivalent magnetic field at the on the parallel plane of the Magnetic North for the MP point in question due to the symmetry of the flux lines and the sum of all the components are added at the center of the wire loop.

The next step is to incorporate the Biot-Savart Law to obtain the magnitude and direction of B at the MP latitude, Longitude given along with alt  the inclination angle.  From Figure 2.11, we can derive the parallel contribution as alt =  altcos(alt )  then the magnitude of the intensity is defined as altalt / cos(alt ).  Applying Boit-Savart Law for the parallel contribution becomes:

alt

Equation 2.1 Biot-Savart Law
alt is basically the circumference of the wire Loop

alt  

 Then:alt

Evaluating the Integrals  alt, alt (Big Jump forward for convenience)
From the Givens above we have:
N = Number of turns of the loop, The       
circumference just increases by N
I = Current applied to the loop in ampere
alt = Inclination xx
° of Latitude, Longitude

alt

Equation 2.2 - Parallel (Horizontal) Field

alt

Equation 2.3 - Total  Intensity at inclination alt

OK, to test this go to Goggle map and set your location and get the Latitude, Longitude from Goggle map and enter them into the NOAA NCEI calculator, (NOAA site also allows you to enter a physical address as well) that will give you all the magnetic field information of the Lat, Long you entered. The result is a table similar to Figure 2.12 below.   Of course you will require a tangent galvanometer, which we will be building for the next part of the series.  They are very easy to build and all the parts are under $12.00 all locally obtained for those that want to build their own to follow the series.

alt
Figure 2.12  Magnetic Field  32.423831, 110.995709

OK, now that we have an understanding of the Earth's magnetic fields lets see how this will help us out with the IoT Core Platform Development.  Over 20 years ago Honeywell corp released a device to the public that would measure magnetic fields down to the micro-Tesla levels on a small integrated circuit.  Today you can purchase these IC's for under $2.00, also several manufacturers have used these devices to perform 3D magnetic field measurements of a point X,Y,Z from an EM source.  We will present these devices when we move forward with the Interface for the IoT Platform.  The industry advanced to a technology level that these Magnetic field sensors are used in so many places side by side with GPS devices, manufacturing process control systems and more.

SUMMARY
OK, this was a long exercise for this part of the series and if you are wondering why we went through this exercise and what does this have to do with Wave Propagation, Antennas and radiation, well it is simple.  The Earth is a continuous source of magnetic radiant energy in this place we call space and has a direct effect on all life forms on this planet.  The Earth also has magnetic oscillations or frequencies that are unique to its structure and to understand the Earth's magnetic frequencies and forces we have to start at the real basics of what science already knows from experimentation.  The Magnetic radiant frequencies are important to all life forms on this planet and as we move forward we will see how interfering with these frequencies disrupts the resonance of life forms as well.  This will also set as a reference of radiation or EM waves that are healthy to all life forms as well as to give a brief overview of what is ahead in this series.  Our point here is to understand that the magnetic "fields" vary as a function of Energy, Frequency and Vibrations and the best that science has to offer at this time are mathematical representations from empirical evidence.

So from this part we have shown that a EM field is generated from a constant current and it does transmit for a distance in air-space.  This would be the same if the current was oscillating at a frequency bands which we will get to in this series.  Also we see that the field energy is reduced as we move further away from the source current generating the field.  It is difficult to discuss magnetism without mentioning at least one of Maxwell Laws since Maxwell combined many of the different electromagnetic laws into basically four laws and what we presented here was a version of the fourth law.

We are constructing a few of the Tangent Galvanometer for our lab measurements later in the series at different transmission frequencies up to 100GHz in order to measure the radiation at specific points of transmission path since many of the EMF meters today on got as high as 8GHz a couple up to 10GHz.  The construction plans will be presented as the series moves forward.

As the series progresses the author, Sal Tuzzo will be available for discussion through the BASIL Networks Contact Form for those that want to apply this series to conduct their own experiments.  The Author is always be appreciative for the private comments sent through the contact form for suggestions and advice during the development of this series.  This is a growing opportunity for everyone entering into RF product development arena as well as a great review for us "well seasoned" in the field to just refresh our human DRAM (Dynamic Random Access Memory).

It is recommended for those that have specific questions on the series to use the BASIL Networks Contact Form to separate them from getting lost in the general comments for each blog presentation.  For all specific design request or contracts please feel free to contact us.


Part 3...n  Preliminary Outline for the series "Basic Wave Phenomenon Antennas & Radiation" -Continued
There are many more Laws of energy transmission in the wireless arena that will be addressed as the series progresses showing the relationships between them and how they relate to the wireless communications as they are applied today.  Energy distribution laws we will address are:  Planks Law,   Stefan-Boltzmann Law,  Maxwell-Boltzmann Distribution Law,  Wien Displacement law,  Emissivity,  Kirchoff's Law,   Lambert's Law also know as the Beer-Lambert Law,  So as we see there are many theories that have been experimented with however, with all these laws there are still anomalous deviations that seem to fall outside the norm which we will discus later in the series.


Wave_Index Quick Links


Reference:
The books in these references are my Northeastern University college of engineering text books except for the Ultra-High-Frequency Techniques, that was a gift from a colleague.

Ultra - High - Frequency Techniques (1942  D. Van Nostrand Company)
    J.G. Brainerd,  Professor EE Univ. of Pennsylvania
    Glenn Koehler, Assistant Prof. EE Univ Wisconsin 
    Herbert J. Reigh,  Prof. EE Univ. Illinois
    L.F. Woodruff, Assoc Prof. EE  MIT Massachusetts

Wave Propagation and Antennas (1958 Library of Congress: 58-9431) by George B. Welch Professor of Physics Northeastern University and Professor Hollis S. Baird whom I have had the honor of being one of his students.
Basic Microwaves (1966 Library of Congress: 65-16814) Bernard Berkowitz
Physics (1966 -ISBN: 0 471 71715 0) Robert Resnic and David Halliday Part I
Physics (1960 -Library of Congress: 62-15336) ) Robert Resnic and David Halliday Part II
Fundamentals of Physics  Revised Printing (1974 ISBN 0471-34431-1) Robert Resnic and David Halliday
Signals in Linear Circuits (1974 ISBN 0-395-16971-2) Jose B. Cruz and M.E. Van Vlakenburg

Wikipedia - On-Line Knowledge Center


Publishing this series on a website or reprinting is authorized by displaying the following, including the hyperlink to BASIL Networks, PLLC either at the beginning or end of each part.
BASIL Networks, PLLC - Wave Phenomenon, Antennas & Radiation Part-2 Electromagnetic (EH) Waves-A few more definitions for the series: (May 8, 2020)

For Website Link: cut and past this code:

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[Sal_TUzzo]

Sal (JT) Tuzzo - Founder CEO/CTO BASIL Networks, PLLC.
Sal may be contacted directly through this sites Contact Form or
through LinkedIn

23 Mar, 2020

Internet of Things (IoT) Security, Privacy, Safety -Platform Development Project Part-21

Part 21: IoT Core Platform Development;- Peripheral I/O Device Design
The IoT Embedded Core Platform -Peripheral Devices Real World Testing - Continued (Update May 14, 2020)

"The first rule of any technology used in a business is that automation applied to an efficient operation will magnify the efficiency.  The second is that automation applied to an inefficient operation will magnify the inefficiency." ( Bill Gates - Oct 28 1955 - )

As we stated in past presentations in this series development costs are easily exceeded when the performance expectations and in that case performance requirements are not documented properly, hence: the infamous "TBD" -To Be Determined.  This forces a direction change "AND" direction changes are commonly not listed as part of  performance expectations.  Sometimes the development "process" is faulty or just plain broken period.  The intent of this series in not to maintain the insanity of over budget development costs but to disrupt it in order to allow the creation of new habits that will give a solid foundation for engineering practices to be successful when starting a development project.

For the new designer that is taking on the learning of CPLD and FPGA design, "Each design completed is experience for the next lever of development."  There are only experiences and techniques that will bring you to the advanced level of applications.

IoT_Index Quick Links

Quick review to set the atmosphere for Part 21:
Every new year technology advancements exceed the previous years, we get to apply some new technologies released to gain experience.  This past year 2019 many new devices and IC emerged on the market for developers and applications for the IoT arena.  We will address some of the new devices and in fact may have an impact on our IoT Core development series.  This is the new reality of product development in a fast changing technology environment, sometimes the product becomes obsolete before you are able to get it to market.  Project management becomes a bit challenging when faced with obsolescence during development   Simple buy for the end of life becomes a marketing nightmare knowing that the competition will release a competitive product with the latest hardware while your product is using obsolete or discontinued components.  Designers and development integration becomes a real design dilemma determining if the replacement "If There Is One" will cost a complete redesign or a firmware/Software update and more.

So as of this writing here is what has been happening in the micro silicon embedded world,   A couple of new embedded processors have emerged from all the Mergers & Acquisitions and many processors have been discontinued.  Performance and features such as higher core speeds and multiple cores make it applicable to many AI (Artificial Intelligent) applications.  Several interface ICs have been released that may help the interface sensors etc. along, however careful consideration has to be taken to insure that the interface will be around for at least five years to accommodate the embedded lifecycle requirements.

It is easy to loose focus on the project with all the new technology being released so a quick review to remain focused on the series.  This series is focused on the development of a Core Platform IoT applications and has a dual purpose, first an educational project development for the entrepreneurial mindset along with applications, second the implementation of remote sensing and control incorporating safety, security and privacy over a wide range of peripherals including wireless.  This should be kept in mind since we will be designing in some redundancy for reliability and security.  For the yourg newcommer to product design and development if you are chosed to be mentored by a senior accept humbly, it will be the most rewarding experience of earned knowledge you will every have.  

Since the wireless industry and advanced since the introduction of the IoT devices we have also started a new series on Wireless technology in a separate category, Wave Phenomenon, Antennas & Radiation in the category of Wave Propagation and Antennas.

The ITF development Project:
The ITF did create a change in direction, however did not change the desired results, this is not only common in development projects but is some cases required to meet the desired expectations.  The issues here are handling multiple projects, resources available and the changed timeline, just a short change in direction to complete the objective.  A validation that the real time product development process is far from being a linear process from conception to finished product.

Remember changing direction overnight does not mean changing goals our the final destination, it is just a better way to insure you will reach the desired destination.  In my years of exposure to the design arena as a designer, troubleshooter and mentor I have had the honor of experiencing innovative and passionate creators to realize that the creative thought process of an individual is not a linear step function, 1, 2, 3 ...N, probably because humans are not robots, that follow a preprogrammed set of processes as some may think of engineers.  The innovation of the human mind subconsciously is always performing scenarios to find the best solution for the task at hand and "developing habits along the way".

We will pick up from the last couple of parts in the series that cover CPLD#1 and CPLD#2 to put us in perspective for a complex design.  In Part-19 the digital I/O section of the ITF which included CPLD #2 was presented.  Due to the complexity and size of the blog only the first part of the Digital I/O was presented which included the following sections.

In Part-20 the continuation of the digital I/O design which included the internals of CPLD#2 registers, preliminary flow diagram and pin requirements of the CPLD and the first pass CPLD#2 design.  The important part of this section was the templates for tracking and creating PCB footprints by pin number and pin names.

What we want to cover in Part 21:
In Part-16 through 20 we addressed the issue of why we should consider testing of the peripherals (Proof of Design) PoD with a prototype build to insure when we interconnect several of the peripherals the throughput required for the applications will be met.  This allows the opportunity to change the development direction from the peripheral point of view if performance expectations become an issue. Developing a test methodology that will be used for testing peripherals for the platform keeping in mind peripheral throughput limitations. These are new habits being developed at a conscience mind set level that will connect to become the default critical thought process during development.  With that stated we will continue moving forward with detailing the Interface Test Fixture (ITF) CPLD #2.

Updating the IPD project documentation for the ITF (Interface Test Fixture) to keep track of the development process, "Documentation is a living process during development", a good habit to make!  The reference for the ITF is the functional block diagram Figure 16.1

Lets Get Started:

Some questions answered from our readers
"What happen to the series?,
"It has been a few months since part 20 publication, are you going to continue the series?
To answer the above two questions - YES the series will continue.   BASIL Networks, PLLC own and maintain several on-line servers as well as off-line servers all located on-site. We are in the process of upgrading them to the latest and greatest compliant requirements aw with all upgrade and new installations this took "longer" than planned, HHMMmm I think I said that about product development timing some where, well again we have added another first hand experience to our portfolio. Cool   We also started a new blog design category as we stated several times in this series about wireless and security, this new blog is addressing the wireless section and as always we start at the very basics and work up to the expert level for our readers.  The new blog is Wireless, Radiation and Antennas.  Yes, I know it was mentioned and linked a few paragraphs back. It is the old poetic license of repeating ones self three times, so that leaves one more time somewhere in this part.

Refresher on Security,  CPU Code and Encryption:
When designing products that are controlled by some type of processor keeping a security mindset should always be an active part of the design process.  There are several sections of a security policy to be taken into consideration when designing any product that will be connected to a network be it global or local.   Access security implementation is by far the most time driven authentication process today.  From Single Password Authentication to Multi-Factor-Authentication software driven it takes time to access and perform all the decryption, table look-ups and more.  Most financial and many government sites have incorporated MFA and generally it is less expensive to incorporate a software change than to upgrade physical hardware.  A few of the top level questions to address for the security poplicy are:  Who will be accessing the device?,   What type(s) of encryption to use?,  Who owns the keys?,  Are the encryption keys changeable?,  are just the few top level ones.  We will cover a few ways of insuring security and privacy for the IoT Core Platform as we move forward.

OK, why the security refresher?  This is where we incorporate the mindset to design in access security, proivacy and safety for the I/O part of the IoT Platform.  What does this have to do with the Core IoT Platform?  Putting security in the ITF allows us to test different access methodologies for access control.  For the ITF the design incorporates the CPLDs internal FLASH that will allow the user to embed a series of encryption keys as well as ITF device serial number, and other identifying characteristics which may also be encrypted and assigned to a specific PC it is used with for added security.

It is much easier to incorporate hardware access security in the initial design stage than attempting to add a hardware security feature after the design is complete with some type of after thought patch.  The MAX-II  EPM1270T144C3 incorporates an 8192 bit FLASH that may be organized by byte or word and configured during the CPLD programming stage as 1024x8 or 512x16.  By enabling the security bit the FLASH and the CPLD configuration are not readable to the user, however the ability to completely erase the device remains, keeping the data from being read.  This is a good start, however we still have to create a security policy to implement into the CPLD FLASH.  This is addressed later in the series.

ITF CPLD#1 A/D vs CPLD#2 Data I/O Peripheral:
A brief comparison of the CPLD#1 A/D design and CPLD #2 High Speed Digital I/O Design.  Both incorporate a SRAM buffer to collect data at a periodic programmable rate or manually triggered externally.  However the design parameters are completely different, for one the high speed digital I/O requires a 10ns static RAM and the A/D is much slower 1us conversion time so a 1 typical PSRAM of 55ns is sufficient and much less costly.

A/D Channel vs Data I/O Throughput 
A quick comparison of the two technologies, the A/D Channel is a 1 us Sample rate via a 50MHz 16 bit  (20ns x16) Serial interface.  The actual conversion time is approximately 700 ns which allows ample time for the serial data to be transferred into the PSRAM on board without missing any points until the number of samples has been obtained.

The Parallel 16 bit interface in CPLD #2 is different since we require the full 50 MHz or faster x16 bit transfer rate without missing points.  This simply states that the full time cycle to write to memory is less than 20ns in order to meet the 50 MHz transfer rate.  The main difference is that the memory type for this requires a full Static RAM type of 10ns or faster verses a Pseudo SRAM type of speeds 70ns typical.  The faster the SRAM the higher the cost also the faster the throughput and the more power required which generates more heat.  There are a smaller selection to choose from when designing with 10ns or faster SRAM devices.  There is a list in the Reference Links of the selected high speed SRAM devices for this project at this time.

Peripheral vs. Functions
When designing any product including test fixtures the Peripheral vs Function discussion will always arise to insure the best price per performance is addressed.  With the technology advancing at such a rapid rate ICs are being release on a regular basis to eliminate support ICs as well as reduce design and testing time.  There are pros and cons with all designs and they have to be addressed.  The approach we are applying in the development of the ITF is flexibility and programmability and separating the front end sensing to separate IC(s).

Create a Preliminary Timing Diagram
As we stated before creating a preliminary timing diagram of the expected performance takes some practice and is always recommended for speeds that get close to the limits of the CPLD and will aid in troubleshooting timing propagation delays after programming.  Figure 21.0 is the preliminary timing diagram for CPLD #2 and as we see it would require capturing the data in a 5 ns window in order to be ready for processing in 10ns.

The other issue is as we review the pin count it appears that will not be room to incorporate the designs for the serial ports, hence, the SPI, I2C and QSPI types of protocols.  We could always incorporate a third CPLD, however it may be better to actually use the 16 bit interface and create the serial interface CPLD as an actual IoT Platform serial Interface then use the IFT to test the data transfer for the IoT Peripheral device itself.  Remember the IoT Platform I/O will remain a constant while the processors evolve. The expectations is to design a 10ns data throughput interface with the maximum data width possible.

alt
Figure 21.0   CPLD #2  Preliminary Timing Diagram

From the IDE functional block diagram in Part-20 and the Preliminary timing diagram above we should be able to easily create the simulated IDE logic timing diagram with all the delays and the DMA performance for CPLD #2.  The IDE release 19.1 Quartus Prime Lite Edition for the CPLD is available for download in the Reference section below.  We will use an older release 9.1sp1 for this design for the time being since we have not had the time to fully evaluate the new release and test the differences that have been completed to date. To keep this consistent we will recompile later after the design is complete and compare the differences in releases.  Prior to Intel/Altera M&A Altera several of the releases of Quartus Web incorporated sets of different CPLDs and selected FPGA and they recommended that you use the release that is required for the device of choice, however a lot has changed since Intel is now merging this with their product line.  We have to look at redesigning several in-house devices since they were discontinued that has caused some issues in the lab as many R&D labs have encountered.  

During the timing setup a few design issues came up that have to be addressed.  The Functional block diagram is correct, however the implementation of the design has limitations and will not meet the expected throughput.  So what is missing for the CPLD #2 design that should have been presented at this time.  Lets take a look at what preliminary design procedure requirements for CPLD #2.

We have the following completed

OK, what we have left out is the preliminary functions I/O Register Map assignments.   Why do we want to do this prior to the design, well, since we did not create it on a spreadsheet the programmer will have to figure this out, not a good idea.  What could possibly go wrong if we just do it later? The black hole cliche of all times.  So lets complete the process requirements, it is easy to just not use a bit in a register than it is to try and add one later.

There are many schools of thought on register implementation for peripherals and there are same implementations that make it extremely challenging for software to get around and are not recommended.  Some general guidelines of register implementation to follow that insures a hardware/software balance.:

Following these guidelines allows the software configuration to be grouped in a contained block of memory to be easily programmed and viewed.  The register sets for CPLD #2 are all eight bit (byte) registers to meet the pin count of the 144 pin CPLD and leave a few pins for modifications.  A good rule of thumb to follow is always try and stay below 80% of the available capacity of the device using to allow manual changes to the routing to address unique propagation delays..

Peripheral Control/Status Register = 8 Bits - 1 byte wide register

From the above list CPLD #2 requires 14 byte wide registers for setting up the peripherals functions as well as the 14 control lines to load each of these registers. This is a good place to start.  The front end of CPLD #2 for the Register set would require 5 bits to address the uo to 32 registers and control strobe lines combined to initiate the device manually and set the different mode configurations.

CPLD Simple Propagation Delay Test
In Part-14 we touched lightly on the internals of the CPLD connection matrix and the internal Logic Element blocks. This is one of the areas that many talented engineers are stilled challenged with and it is not going away either. It is the internal connection matrix that contributes to those propagation delays that make or break a design.  Just because a design works with the fastest speed device and you are below or within the lower speed device parameters that costs less does not mean the lower speed device will work the same way.  Connections matrix is a large contributor to propagation delays however complexity and available Logic Element gates and where they are between Logic Element blocks adds to the interconnection issues.  Here in the lab we have experienced this many times where we pushed the CPLD to 90% of resources and changed speeds and still had to redesign the CPLD to make it work.  Now take this understanding and think you can easily change manufacturers or CPLD series and expect it to perform the same or better without real world testing.  One of the areas we have found to be root cause of failure is with major bit shift switching from 111100001111.  The matrix in a CPLD are not neat and organized as if you would hand wire it, they are routed via an algorithm similar to auto route in a PCB and that can get cluttered.

The typical misconception with programmable logic devices from engineers and engineering managers that have not had the opportunity to actually design with them is "Oh, just make changes to the CPLD/FPGA and we do not have to run a new PCB", well folks that is not a good thought process to be transmitting.  As we will see below the same design acts completely different with just a change of the device speed and nothing else.  Propagation delays are variable depending on the complexity of the design.  Internal noise (crosstalk) with adjacent interconnection planes can cause false triggering and other types of spikes throughout the device.

Ok, now that we have created a preliminary timing diagram for CPLD#2 of the critical data flow of the memory data I/O it is time to encourage good design behavior when designing with CPLDs and FPGAs.  A good general practice when designing with CPLDs or FPGAs is to test the waters on speed and general throughput when attempting to push the limits.  Sometimes boolean logic just seams illogical when it comes to connecting points in a CPLD and FPGA matrix.  To Test the CPLD being used, a simple circuit was compiled and simulated to show the timing diagram of the functions shown in Figure 21,1 incorporating a simple pipeline binary decoder 1 bit to 2 line and 2bit to 4 line decoders with an gated clock.

IMAGE_CPLD_TEST
Figure 21.1   CPLD #2  Speed Test Function

The expected digital sequence for this design is shown in Figure 21.2 and is a basic binary decoder 2 and 4 line with a front end latch for one clock delay.  The front end latch is to insure that the decoder input is presented with the binary bits all at the same time in order to eliminate spikes that will cause other timing issues.  The GateEN is the standard D-Type F/F and it operates on the rising edge of the clock and is expected to respond in less than 1ns.  Figure 21.2 shows what is expected and the simulation results Figure 21.3 and 21.4 are two different results.  This is one of the reasons it is encouraged to create an expected digital timing diagram when ever possible prior to actually using the IDE to design the CPLD or FPGA.  Over the years we have found that the simulation process with IDE's does perform well, however being able to simulate all functions for the design is where many fall short and the problems show up in real world application after the product is on the market.

CPLD_2_Expected_Timing
Figure 21.2   CPLD #2  Pre-Timing Diagram Expected 

To start the highest speed CPLD available was selected for the simulation for the test design in Figure 21.1.  Figure 21.3 shows the simulated timing for the 144 pin device selected.  To understand the propagation effects of speed to configuration of the CPLD we will run the same timing simulation but with the slower device.  The CPLD The actual part for this simulation test is the EPM1270T144C3 for the fastest speed and EPM1270T144C5 for the slowest speed both handle speeds faster than 10ns.

CPLD-Test-SimTimingScaled.jpg
Figure 21.3   CPLD #2  Speed Test Simulated Timing Fastest Device (C3) 1270LE Timing

Observing the two timing diagrams we easily see that the device becomes unstable at the same frequency.  When we look at the pin to pin delays for the different speed devices C3 vs C5 we get 6.3ns and 10.1ns respectively.

CPLD_Test-SimC5Scaled.jpg
Figure 21.4   CPLD #2  Speed Test Simulated Timing Slow Device (C5) 1270LE

Keeping the same design just changing from a 1270 Logic Element device to a 570 element device Form Fit Function the results for the C3 devices are also very different as shown in Figure 21.5 below.  The MAX-II EPM1270T144C3 and the EPM570T144C3 are form fit pin interchangeable however the performance differ greatly with just a simple design configuration.  Timing changes with complexity and pin assignments as well.  When we look at the pin to pin delays for the different architecture 1270LE C3 vs 570LE C3 speed devices we get 6.3ns and 5.5ns respectively.

CPLD-Test-SimC5-570Scaled.jpg
Figure 21.5   CPLD #2  Speed Test Simulated Timing Fast Device (C3) 570LE

The question is what is the stable operating frequency for the devices.  We ran a series of test frequencies from 10ns to 1ns clocks  and the high speed device was selected as well as adding some delay functions in the clock line.  When you get below 10 ns it is very typical that you will run into propagation delay issues when as the available LEs (Logic Elements) of the CPLD become part of the design.  The experience we have seen here in the lab is every unique interconnecting trace adds about 0.4ns delay so if you have to go through 3 unique interconnects before you get to the pin you already exceeded the clock time of 1.5 ns for a 3ns clock cycle as shown in the timing diagrams.  Looking at Figure 21.4 we see that the propagation delays for DOUT2 exceed the clock and the output is completely missing.   Also DOUTA and DOUTB overlap which would cause other timing issues if DOUTB must start after DOUTA ends.  OK, now think of the fact that manufacturers make design updates to these devices at random. This makes interchangeability a very risky business for critical reliability devices.

There are ways to compartmentalize the design and keep the I/O ports for the section close to the LE and not split them between several LEs.  After thought additions is where the problems arise the most since the addition may have to reconfigure the CPLD differentially to accommodate the functionality designed in and the device becomes unstable.  The in-depth analysis of CPLDs and FPGAs go beyond the scope of this blog series however, it is important to present some of the challenges attributed to CPLD design when designing peripherals since the majority of designs today incorporate some from of programmable logic.  As a refresher on why the 144 pin CPLD was selected, mainly because it has been around for many years, designed into many devices with no end of life in sight at this time.  The MAX II and the MAX V are 2 different pins, MAX-II has 116 I/O pins and MAX-V has 114 pins.  We have not tested the performance or Form Fit Function physically in the lab since all our designs use the MAX-II and the devices are still readily available for all levels of designs.   Although the selected device is more costly the choice for same performance the MAX-II EPM1270T144C3 is the one we will use for this design. If this were going into a large volume product a separate PCB attached to the ITF could be used to AQL (Acceptable Quality Limit) evaluation of devices per lot.

Register & Bit Assignments
The correct design sequence is to create the CPLD #2 register map first, then create the bit assignments for each register prior to the actual design of the CPDL.  Yes, we did this backwards not just to show the time it requires to undo the design then implement the new updates, but in this case we attempted to try and reuse some of the assignments from the reuse design library.  The reuse design was taken from another project that involved a memory buffer.  Well the implement of the reuse parts and adding some functions that are required for this design just added more delays which  from several years experience with timing delays it would be better to just redesign the CPLD from scratch..  This is typical of many reuse scenarios and will now cost more time to undo and redo the design, this is our learning curve on using a design that are close to what we wanted but not exact.  Also when we canalized the propagation delays the throughput transfer speed also fell short of the expectations.  

The Register and Bit Assignments will be presented in Part-22 of the series along with spreadsheet templates.

How to Obtain a Finished ITF:
Our plans when the ITF is finished, is to offer an ITF to the public that has many more features than the one being developed for this presentation.  We already have completed two different PoD products to get ready for manufacturing and offering custom development for contract manufacturing companies and the entrepreneur small company that want to setup a development test base for future and present development contracts.  Please use the BASIL Networks Contact Form to be put on a mailing list when we are ready to supply the manufacturing prints if you are interested in purchasing the entire system manufactured and tested.

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SUMMARY:
OK, this is a lot to present in a single part as with most of the parts of this series as we dive deeper into the designing devices.  The reuse of similar designs has it pros and cons, in this case it was a con since the timing of the design caused the redesign of the interface.  In many cases modifying a design ends up taking longer and incorporates less functionally that would have been to have the flexibility and freedom to do the design from scratch.  Many discussions with senior engineers and innovators have confirmed this through the years.  The difficulty lies with those that make the decision for the engineer and have not been in the design field for some time.  There is no disrespect meant with that statement, it is just a fact of human nature that when you are away from the details for a while you only focus on the results and not the process to get there; and by the way, as it should be, however when the facts are put on the table those managers (leaders) trust those that are at the detailed level and follow that lead and tend to managing the project.  This behavior of trusting the front line knowledge has been a proven process for a successful project development.  So, why would you have high level knowledgeable individuals on a field of interest drawing a salary and not listen to them? Cool that works the majority of the time and is what a responsible team is not only required but is how a team is expected to perform. It has been said by many of lecturers through the industry from different fields "Engineers design and build cities, Managers run them after they are built".  Ok, end of lecture to encourage engineering and managerial behavior

Updating and Modifying CPLDs / FPGAs
Here in the lab we have been very fortunate until just recently that our internally designed and developed test fixtures have stood the test of time for almost 20 year.  We still have some XP systems still running mainly due to third party PCI cards that will not run in any of our Windows 10 x64 Enterprise systems with PCI slots.  Some of our internally developed test equipment that incorporate discontinued CPLDs have to be redesigned.  When we looked at the replacement cost of some COTS instrumentation the lab requirements were just not available in a single product as well as the price being out of the expected budget.  The best approach is still to design the test fixtures to meet our needs with components that are anticipated to be around several years.

As shown in the above in Figures 21.1.through 21.5 FFF (Form, Fit, Function) does work but not exactly the same propagation delays add a high risk for critical equipment. This FFF discontinuity is also effective by revision changes in the IC itself.  Several programmable logic IC manufacturers have pin-to-pin replacement for their series of CPLDs, however think of a revision change in one of the devices that are labeled FFF in the series and is changed out for more LE's  or to add to that a different manufacturer and a new PCB layout.  We all get the picture now; so what is the solution.?  Building a physical prototype and test, test and test again for all functionality.   

Over the years the major contributions to the timing and propagation issues were designs focused for the selected CPLD / FPGA series that approached the maximum resources available in the device. This contributed to major carry glitches usually four bit and above blocks  111100001111 along with the data path within the interconnecting matrix for the chip.  As we see the FFF factor sort of falls from the rooftop of a tall building when upgrading to the next pin interchangeable device in the series.  What we also be noticed is using actual I/O pins as test points in the simulation since they are also routed through the connections matrix, when removed from the final design the device also performs different.  Many engineers use internal pin assigned names that are simulated at the point inside the chip that are picked which will change the timing as well.  The big pro of programmable logic devices is that you can change the design of a device and use the same PCB.  A major con of programmable logic devices is that the propagation times change as the density changes for the application and compensation gates have to be added to insure stability and functionality of the device.

This update to the ITF section adds a single channel DMA controller that is shared as a Digital Logic Analyse for monitoring CPU BUS timing.  This becomes a very useful reuse design since not all designs will survive the reuse environment as we mentioned previously, only about 5% will be a true total Plug'N'Play reuse.  Experience has shown that FPGA and CPLD designs that incorporate the simplest of modifications have the risk of reduced performance, it is the nature of the beast.  We selected the larger of the MAX-II Logic Units to allow optimization and future additions if required.

Quartus 9.1 to Prime Lite 19.1 Timing simulation comparison:
The timing test was run on Release 9.1 and 19.1 the results were different for the same tests.  Release 19.1 has better routing optimization and also allows both functional and timing simulation that concur with both devices in the same family and speeds.  This is a good thing since we will be updating to release 19.1 when we update the custom equipment in the lab.  These are important issues for all in house equipment since we have talk to several labs some still running XP and are forced to remain on older versions.  An update will be presented as we continue to test and replace obsolete CPLD and FPGA devices

CPLD Register Identification
Since we neglected this because of the Reuse factor the thought was since the design matrix was already defined prior all that would have to be done is reassigning the bits for each register.  Well renaming the registers and bits did not turn out as expected and, oh by the way to make it clear; "It Very Seldom Does work as expected."  So, re-mapping the registers is required, that ok, however the complexities became clear that re-mapping lead to changing functions sequences and that lead to other changes and it soon became obvious when we started modifying the design the 50% mark of changes were present and the end is not clear.  At that point purely by experience it was decided to just start from scratch and layout the CPLD to fit the application with a few spare I/O pins for future growth.  In this reuse case it was fortunate that the redesign was recognized early before many man hours of troubleshooting and development were lost.

Final Note
Changing poor engineering habits are difficult however not impossible to correct.   Humans are very flexible they all have the ability of learning anything with applied effort, the only impasse is the mind set that if negative will defeat any attempt to grow and instill fear of learning.  The key is to acknowledge the initial behavior, no it will not change overnight - it took a while to become rooted.  Bringing the development behavior to the surface and acknowledging the behavior is the first step in this series to bring the development process to a winning level.   The expectations of this and other series on the blog is to encourage the behavioral changes as well as present a project that is useful for many applications.  Behavioral modifications is a personal and private process that takes time and requires trust within ones self.  

As the series progresses the author, Sal Tuzzo will be available for discussion through the BASIL Networks Contact Form for those that want to apply this series to conduct their own experiments.  I will always be appreciative for the private comments sent through the contact form for suggestions and advice during the development of this series.  This is a growing opportunity for everyone entering into product development as well as a great review for us "well seasoned" in the field to just refresh our human DRAM (Dynamic Random Access Memory).

It is recommended for those that have specific questions to use the BASIL Networks Contact Form for questions to separate them from getting lost in the general comments for each blog presentation.  For all specific design request or contracts please feel free to contact me.


Reference Links:

ITF Selected Components

MAX-II EPM1270T144C5  Pin Assignment Template

BOM Spreadsheet and Component datasheets ZIP file

PGA281 Programmable gain Amplifier Datasheet
IS66WVE4M16EBLL 64Mbit (4M x16) Pseudo SRAM Datasheet
Alliance Memory AS1C8M16PL 128Mbit (8Meg x16) Pseudo SRAM

Intel®/Altera® Quartus Download 9.1 sp2 from Archives
Intel®/Altera® Quartus Lite 19.x Download

Requirements Traceability Matrix  (RTM)
Project Management
Mezzanine Board

The majority of Internet scheme and protocol information are from a few open public information sources on the net, IETF (Internet Engineering Task Force) RFC's that explain details on the application of the protocols used for both IPv4 and IPv6 as well as experimental protocols for the next generation Internet and the Network Sorcery web site.  The remaining of this series on the IoT platform will be from BASIL Networks MDM (Modular Design Methodology) applied with the Socratic teaching method.   Thank You - expand your horizon- Sal Tuzzo

Network Sorcery: http://www.networksorcery.com
The Internet Engineering task Force: IETF - RFC references
Wikipedia https://en.wikipedia.org/wiki/Main_Page

Memory Segmentation
The Memory Management Unit (MMU)
Virtual Address Space
Virtual Addresses and Page Tables
Extended Memory


Previous Part 20 IoT Core Platform - Peripheral I/O Development - Peripheral Device Real World Testing -Continued(Nov  3rd, 2019)

 

IoT-Index


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Sal may be contacted directly through this sites Contact Form or
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