在DSP上实现FFT算法

void FFT( COMPLEX *Y, int N) /* input sample array, number of points*/

{

COMPLEX temp1,temp2 /*temporary storage variables */

int i,j,k /*loop counter variables */

int upper_leg, lower_leg/*index of upper/lower butterfly leg */

int leg_diff/*difference between upper/lower leg */

int num_stages=0/*number of FFT stages, or iterations */

int index, step /*index and step between twiddle factor*/

/* log(base 2) of # of points = # of stages */

i=1

do

{

num_stages+=1

i = i *2

} while (i!=N)

/* starting difference between upper and lower butterfly legs*/

leg_diff = N/2

/* step between values in twiddle factor array twiddle.h */

step = 512 / N

/* For N-point FFT */

for ( i = 0 i <num_stages i++ )

{

index = 0

for ( j = 0j <leg_diff j++ )

{

for ( upper_leg = jupper_leg <N upper_leg += (2*leg_diff) )

{

lower_leg = upper_leg + leg_diff

temp1.real=(Y[upper_leg]).real + (Y[lower_leg]).real

temp1.imag=(Y[upper_leg]).imag + (Y[lower_leg]).imag

temp2.real=(Y[upper_leg]).real - (Y[lower_leg]).real

temp2.imag=(Y[upper_leg]).imag - (Y[lower_leg]).imag

(Y[lower_leg]).real = ((long)temp2.real * (w[index]).real)/8192

(Y[lower_leg]).real -= ((long)temp2.imag * (w[index]).imag)/8192

(Y[lower_leg]).imag = ((long)temp2.real * (w[index]).imag)/8192

(Y[lower_leg]).imag += ((long)temp2.imag * (w[index]).real)/8192

(Y[upper_leg]).real = temp1.real

(Y[upper_leg]).imag = temp1.imag

}

index+=step

}

leg_diff = leg_diff / 2

step *= 2

}

/* bit reversal for resequencing data */

j=0

for ( i=1 i <(N-1) i++ )

{

k = N / 2

while ( k <= j)

{

j = j - k

k >>= 1

}

j = j + k

if ( i <j )

{

temp1.real = (Y[j]).real

temp1.imag = (Y[j]).imag

(Y[j]).real = (Y[i]).real

(Y[j]).imag = (Y[i]).imag

(Y[i]).real = temp1.real

(Y[i]).imag = temp1.imag

}

}

return

}

参考一下的吧，这个是TI官方的在5416上实现的程序~

用CCS编程软件，这是TI公1司DSP的程序编译环境，和C语言编译环境类似，容易上p手3。但是，你在编程的时候最好能找一y些例程来看，这样学起来比0较快，如果你有C语言编程的基础的话就更好了p。另外，硬件方6面需要编程器和开h发板，需要安装驱动。当然，也j可以6不h用硬件编程，CCS有模拟的功能，它利用计1算机的内3存作为8DSP存储器来实现，但是，这种方8法不s能验证你的程序能否在硬件上m正常工z作，是初学者入e门m的最好方4法。j郡kなwan∮m￠撷u薛écvёkな

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