sine1.c.txt

This program produces a Frequency Domain display from the Time Domain * data input using the Fast

/* 
 *  sine.c 
 * 
 *  Version 2.6 by Steve Sampson, Public Domain, November 1988 
 * 
 *  This program is used to generate time domain sinewave data 
 *  for fft.c.  If you want an opening target - negate the 
 *  test frequency. 
 */  
  
#include <STDIO.H>   
#include <ALLOC.H>   
#include <MATH.H>   
  
#define SAMPLES 256   
#define TWO_PI  (2.0 * 3.14159265358979324)   
  
double  Sample, Freq, Time, Real[SAMPLES], Imag[SAMPLES];  
FILE    *Fp;  
  
  
main(argc, argv)  
int argc;  
char    **argv;  
{  
    register int    loop;  
  
    if (argc != 2)  {  
        fprintf(stderr,"Usage: sine output_file\n");  
        exit(1);  
    }  
  
    printf("Input The Test Frequency (Hz) ? ");  
    scanf("%lf", &Freq);  
    printf("Input The Sampling Frequency (Hz) ? ");  
    scanf("%lf", &Sample);  
  
    Sample = 1.0 / Sample;  
    Time   = 0.0;  
  
    for (loop = 0; loop < SAMPLES; loop++)  {  
        Real[loop] =  sin(TWO_PI * Freq * Time);  
        Imag[loop] = -cos(TWO_PI * Freq * Time);  
        Time += Sample;  
    }  
  
    if ((Fp = fopen(*++argv, "wb")) == NULL)  {  
        fprintf(stderr,"sine: Unable to create write file\n");  
        exit(1);  
    }  
  
    fwrite(Real, sizeof(double), SAMPLES, Fp);  
    fwrite(Imag, sizeof(double), SAMPLES, Fp);  
    fclose(Fp);  
  
    putchar('\n');  
  
    exit(0);  
}