Преобразование ФНЧ–ПФ

#include <stdio.h>
#include <string.h>
#include <math.h>
#include "dspl.h"

#define N  2000
#define ORD 5




int main(int argc, char* argv[]) 
{
    double w[N], h[N];
    double bn[ORD+1],   an[ORD+1];
    double bt[2*ORD+1], at[2*ORD+1];
    int k;
    
    void* handle;           /* DSPL handle        */
    handle = dspl_load();   /* Load DSPL function */
        
    
    ellip_ap(1, 40, ORD, bn, an);
    
    for(k = 0; k < ORD+1; k++)
        printf("bn[%d] = %9.3f  an[%d] = %9.3f\n",k,bn[k],k,an[k]);
    
    
    logspace(-2, 3,N, DSPL_SYMMETRIC, w);
    filter_freq_resp(bn, an, ORD, w, N, DSPL_FLAG_ANALOG|DSPL_FLAG_LOGMAG, 
                                                                 h, NULL, NULL);
        
    writetxt(w, h, N, "dat/low2bp_mag_norm.txt");
    
    
    low2bp(bn, an, ORD, 1.0, 5.0, 15.0, bt, at);
    
    logspace(0, 2,N, DSPL_SYMMETRIC, w);
    filter_freq_resp(bt, at, 2*ORD, w, N, DSPL_FLAG_ANALOG|DSPL_FLAG_LOGMAG, 
                                                                 h, NULL, NULL);
    
    for(k = 0; k < 2*ORD+1; k++)
        printf("bt[%d] = %9.3e  at[%d] = %9.3e\n",k, bt[k],k,at[k]);
    writetxt(w, h, N, "dat/low2bp_mag_tr.txt");
    
    
    dspl_free(handle);      /* free dspl handle */
    return 0;
}