Frequency tracking APP

This control App allows you to setup the control algorithm on frequency content to arbitrarily produced siganl.

It is consistent out of the three modules and made with C#/WinForms
NathNumerics HERE is an open source library has been used and installed inside the .NET Visual Studio
Every module has one theme and they are interconnected with function pointers (aka events & delegates), globals and static functions
Each module can work independently but the second cannot be withouth first, and third withoth second (cascade like class composition)
Several timers are used to trigger operations as required by the user, modules have following functionalities

Module 1 is a function generating unit which allows you to generate real-time sinewave composition, pont by point in a given time interval
Module 2 is frequency detection unit which computes self- refreshing spectrum, at once or in a permanent loop
Module 3 is frequency controlling unit which detects frequency shift or expiration in real time

Now this is why the cascade composition has been used: if no signal, no spectrum if no spectrum nothing to control to .

APP Tutorial

Module 1 : FUNCTION GEN.

[1] Time step allows you to control point generation in terms of milliseconds
Number of steps is the equal to number of points where the generation process ends
Chose the sampling rate and press start[4]

Module 1

[2] Chose how many waves should be generated, or turn them on/off during the process
Under [3] you will find real time analysing tools which consist of

True time step measured
Expected time of overall signal generation
Exact time since process started
Bar showing you how much is there to complete the task

At the first opening screen try some simple simulation:

Type 10000 into sampling rate, check all three waves [2]
Press start, if there is sufficiently small number of samples, It will plot all of the three waves

Module 1

Otherwise:

Otherwise if no. steps is some larger number, say 500
Only one curve is plotted for the sake of elegance, like this

Module 1

Now setup some large number of steps
Increase sampling rate and press start ...
while the process is running, press analyse ... now Module 2 opens

Module 2 : SPECTRUM ANALYSER

Run signal generation fast, around 50 msec
Take large amount of points so the process runs continuously in the background
Find some sampling rate that makes all three waves looking nice. (But even if undersampled, this still works ! )

Module 1

Run signal generation fast, around 50 msec
Take large amount of points so the process runs continuously in background
Find some sampling rate that makes all three waves looking nice. But even if undersampled, this app still works

Chose the mathematical method[1]
Press "Refresh" to obtain the "actual" spectrum of your signals generated with module [2]
Set this zoom to some fraction of highest frequency calculated to zoom into the fft [3]
Chose how to plot it, bins, lines or automatically [4]
For as long as generator runs, square indicator is color coded with ilght green, when it turns off it is gray

Module 2

Running measurement in a loop

Check the LOOP: enable radio button [1]

Now set the refreshing rate in msec, usually lower then the signal genrator
In this submenu press start [2]
After your vector of values comming from generator has been filled, you can fix the size of a vector

In this manner it is always going to plot only the no. of values fixed here
This is useful feature because when the whole vector computed with module 1 is observerd
in such a case you would not be observing the spectral changes
(because procedure is obtaining the whole time history within the spectrum)

Therefore after filing the vector of fixed length, you lose here some quality,
but there is an fft spectrum within the last
100, 512, 1024 etc signal values

Module 2

let us see how these ffts look like

Fixing the vector at: last 512 samples
Fixing the vector at: last 1024 samples

Module 2

Module 2

Schematically this is the process being manipulated with "fix bin size"

Module 2

Now press "Enable" button, marked iwth "C" (control)

Module 3: FREQUENCY CONTROL

Thrid module is used to do the following:

In terms of this controlling unit "to lose" some frequency; means it has vanished or it shifted
Module 3 is going to recognize that and process it within the control region of interest
(To see how spectrum is affected, set the function generator differently, turn frequencies off/on or just amplify)

Module 2

Press "Scan" button to copy the instant spectum [1]
[2] If generator is active and spectrum is refreshing both indicator should be "green:
Now Press "Scan several more times" and have spectral overlaps of different time frames->like this

Module 2

Tracking process is highly sensitive to your spectral analyser parameters,
( so once you have copied it do not change setups in previous modules 1, or 2 )
If you still want to change it, press "CLR", clear it all and start all over again
Scroll with a mouse middle wheel over the "treshold" slider to setup the treshold line

Module 2

Now, capture the peak that is of your interest within some bandwidth
Scroll over lower band [1] slider and higher band [2] slider to determine bandwidth of interest
set it up as close as possible: everything outside that window will not be existing for this controller
If the maximum peak drops below the treshold line it is going to be searchd for in the bandwidth
This is determined by the target frequency slider [3]

Module 2

Target frequency is not the exact frequency[4], it is sort of controller "navigation reference"
If this peak moves below its spectral position, or vanishes belwo the treshold, algorithm
recognizes it based on you parametrization
Press [5] and read to see the real peak frequency and magnitude, notice:

real peak is not a target peak
tolerance is a percentage around the target peak
When "Read" pressed if peak is withi the bandwidth and above the treshold there is a message:

FREQUENCY ABOVE THE TRESHOLD
FREQUENCY INSIDE THE CTRL WINDOW.

Module 2

Drop the frequency inside the fun.generator ( or move the bandwith outside the peak )
press the "Read" button now and you the messasge has changed to

" FREQUENCY ESCAPED FROM CTRL- WINDOW .. "

Module 2

Now following situation, frequency for some reason has shifeded outside the bandwidth window
+= and the real shifted peak is within the tolerance region of interest
An algorithm is going to seek for "escaped frequency" within the tolerance region and try to detect it
Noticing you with the message for this case:

      Searching in between frLow: 80,8, frHigh:121,2 // where frLow is tolerance low , and frHigh is tolerance high
      xxxx 
      Frequency inside the tolerance ROI is: 100,034956304619 | value: 0,0798817775983959

Hence , controller has found the frequency inside the tolerance window again ...
Now after understanding this principles, overall setup is going to look like for some middle frequency tracking:

Module 2

Now let us make the report and alert the case of "sudden frequency escape and shifting"
This is a task for module 4. (which is has not been finished at the time)

Module 2