[Help-gsl] Re: FFT(INVFFT) is not returning original data!

[Sumit Adhikari]

A small correction ... "not returning"
Sorry for the inconvenience.


On Mon, Jan 11, 2010 at 3:22 PM, Sumit Adhikari <address@hidden>wrote:

> Hello All,
>   Following function is returning me the original data. Can anybody please
> tell me what is the problem I am doing with it ?
>
>
> # ifndef SC_FFT_H
> # define SC_FFT_H
>
> # include <cmath>
>
> # include "systemc.h"
>
> # include "m_signal_inout_if.h"
> # include "m_signal_in_if.h"
>
>
> # include <gsl/gsl_errno.h>
> # include <gsl/gsl_fft_complex.h>
>
> # include "hann.h"
>
>
> # define REAL(z,i) ((z) [2*(i)])
> # define IMAG(z,i) ((z) [2*(i) + 1])
>
> template < typename T > class sc_fft : public sc_module {
> public :
>    sc_port < m_signal_in_if < T > >          inp ;
>    sc_port < m_signal_inout_if < T > >       out ;
>    sc_port < m_signal_inout_if < bool > >    tx  ;
>    sc_port < m_signal_inout_if < T > >       freq;
>
>
>    typedef sc_fft SC_CURRENT_USER_MODULE ;
>
>    sc_fft(sc_module_name name,const unsigned Nfft,T Offset):
>       inp("inp"),
>       out("out"),
>       tx("tx"),
>       freq("freq"),
>       sc_module(name),
>       _Nfft(Nfft) ,
>       _Offset(Offset) {
>
>          Npoints = _Nfft ;
>
>          i = 0 ;
>
>          fft_inp_buff = (double*) malloc (_Nfft * sizeof(double));
>          fft_inp_buff = new double [_Nfft] ;
>
>          fft_trn_buff = (double*) malloc (2*_Nfft * sizeof(double));
>          fft_trn_buff = new double [2*_Nfft] ;
>
>          fft_out_buff = (double*) malloc (_Nfft * sizeof(double));
>          fft_out_buff = new double [_Nfft] ;
>
>
>          SC_METHOD(read);
>          sensitive << inp ;
>       }
>
>
> private :
>    const unsigned       _Nfft          ;
>    T                    _Offset        ;
>    unsigned             Npoints        ;
>    unsigned             i              ;
>    double*              fft_inp_buff   ;
>    double*              fft_trn_buff   ;
>    double*              fft_out_buff ;
>
>
>    void inline read(){
>       if (i == (Npoints - 1)) {
>          i = 0 ;
>
>          for(int j = 0 ; j < Npoints ; j++) {
>             REAL(fft_trn_buff,j) = fft_inp_buff[j];
>             IMAG(fft_trn_buff,j) = 0.0 ;
>          }
>
>          int fstatus =
> gsl_fft_complex_radix2_forward(fft_trn_buff,1,Npoints);
>          int rstatus =
> gsl_fft_complex_radix2_inverse(fft_trn_buff,1,Npoints);
>          for(int j = 0 ; j < Npoints ; j++) fft_out_buff[j] =
> sqrt(REAL(fft_trn_buff,j)*REAL(fft_trn_buff,j) +
> IMAG(fft_trn_buff,j)*IMAG(fft_trn_buff,j)) ;
>
>
>          fft_inp_buff[i] = (double) (inp->read() - _Offset);
>          out->write((T) fft_out_buff[i]);
>          tx->write(true);
>
>       }
>       else {
>          i ++ ;
>
>          fft_inp_buff[i] = (double) (inp->read() - _Offset) ;
>          out->write((T) fft_out_buff[i]);
>          tx->write(false);
>       }
>
>       freq->write((T) i);
>    }
>
>
> };
>
>
> # endif
>
> Regards,
>
> Sumit
>



-- 

--------------------------------------------
Sumit Adhikari
System Design Engineer
austriamicrosystems AG
Business Unit : Automotive
Mob : 00-91-9885271710/00-91-9000161710