113 lines
2.3 KiB
C
113 lines
2.3 KiB
C
/*
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t48_8.c
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David Rowe
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May 10 2012
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Unit test for 48 to 8 kHz sample rate conversion functions. I
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evaluated output by plotting using Octave and looking for jaggies:
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pl("../unittest/out48.raw",1,3000)
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pl("../unittest/out8.raw",1,3000)
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Listening to it also shows up anything nasty:
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$ play -s -2 -r 48000 out48.raw
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$ play -s -2 -r 8000 out8.raw
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*/
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#include <assert.h>
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#include <math.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "fdmdv.h"
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#define N8 160 /* procssing buffer size at 8 kHz */
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#define N48 (N8*FDMDV_OS)
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#define MEM8 (FDMDV_OS_TAPS/FDMDV_OS)
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#define FRAMES 50
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#define TWO_PI 6.283185307
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#define FS 8000
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#define SINE
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int main() {
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float in8k[MEM8 + N8];
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float out48k[N48];
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short out48k_short[N48];
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FILE *f48;
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float in48k[FDMDV_OS_TAPS + N48];
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float out8k[N48];
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short out8k_short[N8];
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FILE *f8;
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int i,f,t,t1;
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float freq = 800.0;
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f48 = fopen("out48.raw", "wb");
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assert(f48 != NULL);
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f8 = fopen("out8.raw", "wb");
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assert(f8 != NULL);
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/* clear filter memories */
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for(i=0; i<MEM8; i++)
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in8k[i] = 0.0;
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for(i=0; i<FDMDV_OS_TAPS; i++)
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in48k[i] = 0.0;
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t = t1 = 0;
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for(f=0; f<FRAMES; f++) {
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#ifdef DC
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for(i=0; i<N8; i++)
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in8k[MEM8+i] = 16000.0;
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#endif
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#ifdef SINE
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for(i=0; i<N8; i++,t++)
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in8k[MEM8+i] = 16000.0*cos(TWO_PI*t*freq/FS);
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#endif
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/* upsample */
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fdmdv_8_to_48(out48k, &in8k[MEM8], N8);
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/*
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for(i=0; i<MEM8; i++)
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in8k[i] = in8k[i+N8];
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*/
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/* save 48k to disk for plotting and check out */
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for(i=0; i<N48; i++)
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out48k_short[i] = (short)out48k[i];
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fwrite(out48k_short, sizeof(short), N48, f48);
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/* add a 10 kHz spurious signal for fun, we want down sampler to
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knock this out */
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for(i=0; i<N48; i++,t1++)
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in48k[i+FDMDV_OS_TAPS] = out48k[i] + 16000.0*cos(TWO_PI*t1*1E4/FS);
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/* downsample */
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fdmdv_48_to_8(out8k, &in48k[FDMDV_OS_TAPS], N8);
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/*
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for(i=0; i<FDMDV_OS_TAPS; i++)
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in48k[i] = in48k[i+N48];
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*/
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/* save 8k to disk for plotting and check out */
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for(i=0; i<N8; i++)
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out8k_short[i] = (short)out8k[i];
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fwrite(out8k_short, sizeof(short), N8, f8);
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}
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fclose(f48);
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fclose(f8);
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return 0;
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}
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