rfft problem

Started by Sazali Senawi in TMS320c54x18 years ago 1 reply

Hi all; Im still stuck when using the rfft function eventhough Ive followed every advice ive found in the mailing list archive...

Hi all; Im still stuck when using the rfft function eventhough Ive followed every advice ive found in the mailing list archive concerning the rfft. Ive compared the result with Matlab and i still find that the result of rfft is wrong. I really need it to work in order to


Anybody used rfft() from dsplib?

Started by the_believer_1976 in TMS320c54x16 years ago

Good morning, does anyone have C code using cbrev() and rfft() functions of DSP lib? I have noticed that the example given...

Good morning, does anyone have C code using cbrev() and rfft() functions of DSP lib? I have noticed that the example given in \examples\rfft, referred on SPRU518C, page 4-69, calls rfft() right after calling cbrev(). There is something wrong here, as cbrev(


rfft

Started by Matthew Singer in TMS320c54x20 years ago

Anyone know of a publicly available RFFT for the C54 (02 and later 41) that will handle 2K points?

Anyone know of a publicly available RFFT for the C54 (02 and later 41) that will handle 2K points?


problem with rfft

Started by satish_tvs in TMS320c54x18 years ago

hello, i was not able to use rfft and rifft functions provided in dsplib. They are not giving correct results. cfft and cifft...

hello, i was not able to use rfft and rifft functions provided in dsplib. They are not giving correct results. cfft and cifft are working fine. please let me know how to use them or any error is there in the functions itself. satish


RFFT from dsplib not working...

Started by pet_dsp in TMS320c54x16 years ago 3 replies

Hello everybody, I am wondering if any experts here could help solve my problems with using rfft (routine from TI's dsplib)...

Hello everybody, I am wondering if any experts here could help solve my problems with using rfft (routine from TI's dsplib) on a 5402 DSP. Here is my scenario, Codec --> DMA (block size = 256 samples) --> CPU (do 256-pt FFT) --> see results by plot


Spectrum from the RFFT

Started by Guilherme Martinhon in TMS320c54x14 years ago 1 reply

Hello people! I?pm working with the RFFT function and I?m testing my program with a sinusoidal signal with some number of samples and...

Hello people! I?pm working with the RFFT function and I?m testing my program with a sinusoidal signal with some number of samples and different FFT length. But I noticed that the frequency resulting of the DSP is different from the nominal frequency, from the signal generator (seeing on the osciloscope


Interpretation of FFT results

Started by Santosh M Nadig in TMS320c54x19 years ago 1 reply

Hello, Has anyone used the DSP library provided by TI for performing N-point real FFT. It says that when the input is in...

Hello, Has anyone used the DSP library provided by TI for performing N-point real FFT. It says that when the input is in bit-reversed order, the output of rfft() function gives the results as follows.... Re(y(0)) Im(y(Nyquist)) Re(y(1)) Im(y(1)) and so on........but I was not a


FFT

Started by SACHIN JAIN in TMS320c54x18 years ago 1 reply

hi friends, i am using dsk5402 and CCS 2.0 for a real time application and i have to calculate fft. problem 1: i write...

hi friends, i am using dsk5402 and CCS 2.0 for a real time application and i have to calculate fft. problem 1: i write code to configure codec and i used dsplib functions(cbrev and rfft) i have included all related files, then it gives me error:


loss of quantization bits when doing FFT and IFFT

Started by ahgu in TMS320c54x17 years ago

cbrev(x,x,NX/2); rfft(x,NX,1); unpacki(x,NX); cbrev(x,x,NX/2); rifft(x,NX,1); When I get the result back, the data is...

cbrev(x,x,NX/2); rfft(x,NX,1); unpacki(x,NX); cbrev(x,x,NX/2); rifft(x,NX,1); When I get the result back, the data is reduced by a factor of 128. How to do FFT/IFFT without loss of quantization bits? Anyone has routine I can use? thanks A


size of FFT code from DSPLIB

Started by wei_wen_dai in TMS320c54x18 years ago 4 replies

Hi all, I am using the cfft and rfft functions from the TI's DSPLIB. It is mentioned in TI's App Notes (SPRU518) that the code...

Hi all, I am using the cfft and rfft functions from the TI's DSPLIB. It is mentioned in TI's App Notes (SPRU518) that the code size of both functions is about 370 words (plus anoth 360 words for the sintab). However, my output code size increases by nearly 5K if I use on


Using RIFFT and CIFFT

Started by Guilherme Martinhon in TMS320c54x14 years ago 1 reply

Hello people! Does someone in this groups use the RIFFT or CIFFT function? I?m using it, but I can?t reach some results. I?m doing a FFT of a...

Hello people! Does someone in this groups use the RIFFT or CIFFT function? I?m using it, but I can?t reach some results. I?m doing a FFT of a real signal (using RFFT) anda after I want to reconstruct the same signal. As the FFT is a complex signal, I?m using the CIFFT function. My original signal has 256 points. The RFFT256 give only the half of the axis, so it has 128 complex values (256 on ...


Doubts abou Re-Im format

Started by Guilherme Martinhon in TMS320c54x14 years ago

Hello people!   Does someone know where I can found the definition of the Re-Im format? I?d like to know how can I...

Hello people!   Does someone know where I can found the definition of the Re-Im format? I?d like to know how can I interpret the output vector of the Rfft and Cfft functions.


Problems with RFFT/CFFT - DSPlib

Started by Guilherme Martinhon in TMS320c54x14 years ago

Hello!   I?m using the C5416 DSK and now I?m writing a code that do the FFT of a signal generated on the same code....

Hello!   I?m using the C5416 DSK and now I?m writing a code that do the FFT of a signal generated on the same code. I?ve used the cbrev functions, to reverse the bits and a