TDA3XEVM: TDA3x EVE simulator, wrong negative wave FFT result

Sergey Yakubovich

Intellectual 335 points

Part Number: TDA3XEVM

Hi All.

I have few questions, regarding EVE simulator:

Once I provide to EVE negative sinusoidal signal

input_signal = sine();

I got a lot of noise and I did not get proper FFT result (have a look at attached files for positive and negative signals).

I have different amplitude as well.
The scaling factors are zeros and I generate the signal with next Matlab code:

bits = 13;

Fs = 512;

noise_ratio = 0;

sine = dsp.SineWave();

sine.Amplitude = power(2,bits);

sine.Frequency = -11;

sine.SamplesPerFrame = Fs;

sine.SampleRate = Fs;

sine.PhaseOffset = 0*pi;

sine.Method = 'Trigonometric function';

sine.ComplexOutput = true;

sine.OutputDataType = 'single';

Additional information:

When i try to debugging, i found, that reference function:

"vcop_fft_npt_32inter_mixed_radix_cn"

found proper frequencies.

Please advise,

Regards,

Sergey.

over 5 years ago

0 Victor Cheng over 5 years ago

TI__Expert 6335 points

Hi Sergey,

May be there is an issue with the EVE implementation since vcop_fft_npt_32inter_mixed_radix_cn() is correct. What are the FFT parameters you used to initialize the FFT applet ? So I can reproduce the issue with your configuration ?

regards,

Victor

0 Sergey Yakubovich over 5 years ago in reply to Victor Cheng

Intellectual 335 points

Hi Victor.

Thanks for your reply.

My configuration are:

inputData = "../testvecs/input2.txt"
outputData = ""
dopplerCorrectionBuf =
enable32bitsIntermResults = 1
enableDopplerCorrection = 0
dopplerCorrectionScaling = 0
numPoints = 512
numLines = 1
scaleFactor = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
enableOverflowDetection = 0
randSeed = 1
numIter = 1

Please find in attachment my input file.

Regards,

Sergey.

Fullscreen input2.txt Download

0 Victor Cheng over 5 years ago in reply to Sergey Yakubovich

TI__Expert 6335 points

Hi Sergey,

Thanks. I'll try in a couple of days. In the meantime, can you test with enable32bitsIntermResults= 0 ?

regards,

Victor

0 Victor Cheng over 5 years ago in reply to Victor Cheng

TI__Expert 6335 points

Hi Sergey,

Could you test wih enable32bitsIntermResults= 0 ?

regards,

Victor

0 Victor Cheng over 5 years ago in reply to Victor Cheng

TI__Expert 6335 points

Hi Sergey,

I apologize, I haven't had time to look at the issue yet. In the meantime, did you try enable32bitsIntermResults= 0 ?

regards,

Victor

0 Sergey Yakubovich over 5 years ago in reply to Victor Cheng

Intellectual 335 points

Dear Victor.

Thanks for your time.

Finally i compiled the project with VS2012 and all there is no issue anymore.

Thanks,

Regards,

Sergey.

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TDA3XEVM: TDA3x EVE simulator, wrong negative wave FFT result