have trouble with the tktds1k2k driver -- an not activate the fft on the scope, can any one help me with that, thanks

[hilel_s]

I have trouble with the tktds1k2k driver -- can not activate the fft on the scope, can any one help me with that, thanks

 How do I use the tktds1k2k_ConfigureMathFFT function? 

A sample will help .

[EricS.]

There is an example included with the driver, actually.  On my computer it's found in C:\Program Files\IVI Foundation\IVI\Drivers\tktds1k2k

The example is named tktds1k2k_example.c 

And there is a help file as well (tktds1k2k.chm) that explains the tktds1k2k_ConfigureMathFFT function.  When you open the help click "Alphabetical Function Index" and then navigate to tktds1k2k_ConfigureMathFFT.

[hilel_s]

Hello

Thank you for your reply

Actually I need to get  the FFT Graph Data in some scope read function in order to analyze it.

Any Idea how this can be done?

I tried to use the FFT from the CVI signal processing library , but then I encountered the use of complex numbers while in the scope data there is no use of that  and I just cannot figure the units measurement.

I need to see the horz axes -> the frequency in  3khz 6khz .. & the vert horz in 15db 30db ..

How do I get this resolution?  

Any Idea how to handle the matter 

Hilel Shavit

[hilel_s]

Hi

One more thing

Is there a way to could get the command tutorial for the Tektronix TDS 1001B which National Instrumets gracfully engaged itself to develop a driver for this piece of hardware that I am working with. 

by trial and error I can't see I'll reach far. 

Thank you again

Hilel

[8989]

Hi Again

I f I may I'll explain myself again.

• I use an Oscilloscope - Tektronix TDS 1001B  and NI Driver  -  tktds1k2k- for this piece of HW.
• My goal is to perform FFT analyzing using the Oscilloscope built-in function.
• I succeeded to read the array of data that reflects the signal itself, and the sampling frequency, by NI driver.
• I don't seem to find how to read the data related to the FFT as it shown in the scope display.

The two FFT functions supplied with the driver don’t seem to do any reading.

Is there a way through the driver to read the FFT results?

• I am trying another way to perform FFT analyzing - after reading the signal  I get an array of numbers  that reflects the signal.

 I now activate the FFT function from the CVI Signal processing library.

The CVI FFT function have input & output parameters -  a real array and an imaginary array to represent complex numbers.

I put all the signal data on the real array and zeros on the imaginary array.

As a result I get data on the real and imaginary array.

Showing each of the arrays graphically confirms that any one of the array doesn't resemble the display shown in the Tektronix Oscilloscope Signal FFT,

How do I read this CVI lib FFT data?

What are the units of the axes in the cvi  lib fft case??

Why is this real - Imaginary mix in the cvi lib fft function?

Why is there lack of resemblance between the Scope FFT and the CVI Lib FT?

I'll be most obliged for an answer

Hilel

[jr_2005]

You could try using the CVI Spectrum() function instead of the FFT one. It may produce results which more closely match the scope's FFT display.

JR

[EricS.]

I have not looked through this manual myself since I don't have an account at Techtronix' website, but Technronix has a programmer manual for the TDS1001B.  It should include all of the possible functions that you can send to the instrument itself.  It may include something more specific on how to read the FFT data directly back.

These would be sent using the VISA or 488.2 functions from CVI.

You can see a list of all the functions that we included in our driver in the tktds1k2k.chm help file.  Click "Alphabetical Function Index" in the References section.  The instrument may support other commands that we did not include in this driver, so there may be a different function you could call through VISA that would give you the functionality you desire directly from the instrument.

Also, the FFTex function in CVI does not have a complex number input.  It takes a real array input, and outputs a complex array as the result of the fft. You would use this, or the spectrum command as jr_2005 mentioned, on raw time-domain values read from the oscilloscope, not on FFT data read back from the scope.