期末专题老师给了一段程式要求我们改成变声器，或者叫我们自己写。。要求输出的声音能听清楚就可以了，但是改了半天还是无法清晰的听到声音，要从哪里下手呢
// program scrambler.c
#include "DSK6713_AIC23.h" // codec support
Uint32 fs=DSK6713_AIC23_FREQ_16KHZ; //set sampling rate
#define DSK6713_AIC23_INPUT_MIC 0x0015
#define DSK6713_AIC23_INPUT_LINE 0x0011
Uint16 inputsource=DSK6713_AIC23_INPUT_LINE; // select line in
#include "sine160.h"
#include "lp3k64.cof" //filter coefficient file
float yn1, yn2; //filter outputs
float x1[N],x2[N]; //filter delay lines
int index = 0;
interrupt void c_int11()
{
short i;
// first filter input
x1[0] = (float)(input_left_sample()); //get new input into delay line
yn1 = 0.0; //initialise filter output
for (i=0 ; i<N ; i++) yn1 += h[i]*x1[i];
for (i=(N-1) ; i>0 ; i--) x1[i] = x1[i-1];
// next mix with 3300Hz
yn1 *= sine160[index++];
if (index >= NSINE) index = 0;
// now filter again
x2[0] = yn1; //get new input into delay line
yn2 = 0.0; //initialise filter output
for (i=0 ; i<N ; i++) yn2 += h[i]*x2[i];
for (i=(N-1) ; i>0 ; i--) x2[i] = x2[i-1];
output_left_sample((short)(yn2)); //output to codec
return;
}
void main() //main body of program does nothing
{
comm_intr(); //initialise McBSP, AD535
while(1); //infinite loop
}