/* ======================================================================== */ /* TEXAS INSTRUMENTS, INC. */ /* */ /* NAME */ /* DSPF_sp_icfftr2_dif -- Radix-2 DIF Inverse FFT with complex inputs */ /* */ /* USAGE */ /* This routine is C-callable and can be called as: */ /* */ /* void DSPF_sp_icfftr2_dif(float* x, float* w, short n) */ /* */ /* x : input and output sequences (dim-n) (input/output) */ /* x has n complex numbers (2*n SP values). */ /* The real and imaginary values are interleaved in memory. */ /* The input is in bit reversed order and output is in Normal */ /* Order. */ /* w : FFT coefficients (dim-n/2) (input) */ /* w has n/2 complex numbers (n SP values). */ /* FFT coeficients must be in bit-reversed order */ /* The real and imaginary values are interleaved in memory */ /* n : FFT size (input) */ /* */ /* */ /* DESCRIPTION */ /* This routine is used to compute the Inverse, Complex, Radix-2, */ /* Decimation-in-Frequency Fast Fourier Transform of a single */ /* precision complex sequence of size n, and a power of 2. The */ /* routine requires bit-reversed input and bit-reversed coefficents */ /* (twiddle factors) and produces results that are in normal order. */ /* Final scaling by 1/N is not done in this function. */ /* */ /* How To Use */ /* */ /* void main(void) */ /* { */ /* gen_w_r2(w, N); // Generate coefficient table */ /* bit_rev(w, N>>1); // Bit-reverse coefficient table */ /* DSPF_sp_cfftr2_dit(x, w, N); */ /* // radix-2 DIT forward FFT */ /* // input in normal order, output in */ /* // order bit-reversed */ /* */ /* // coefficient table in bit-reversed */ /* // order */ /* DSPF_DSPF_sp_icfftr2_dif(x, w, N); */ /* // Inverse radix 2 FFT */ /* // input in bit-reversed order, */ /* // order output in normal */ /* */ /* // coefficient table in bit-reversed */ /* // order */ /* divide(x, N); // scale inverse FFT output */ /* // result is the same as original */ /* // input */ /* } */ /* */ /* ------------------------------------------------------------------------ */ /* Copyright (c) 2003 Texas Instruments, Incorporated. */ /* All Rights Reserved. */ /* ======================================================================== */ #ifndef DSPF_SP_ICFFTR2_DIF_ #define DSPF_SP_ICFFTR2_DIF_ 1 void DSPF_sp_icfftr2_dif(float * x, float * w, short n); #endif /* ======================================================================== */ /* End of file: dspf_sp_icfftr2_dif.h */ /* ------------------------------------------------------------------------ */ /* Copyright (C) 2003 Texas Instruments, Incorporated. */ /* All Rights Reserved. */ /* ======================================================================== */