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/*
t16_8_short.c
David Rowe
19 August 2014
Unit test for 16 <-> 8 kHz sample rate conversion functions. I
evaluated output by plotting using Octave and looking for jaggies:
pl("../unittest/out16_short.raw",1,3000)
pl("../unittest/out8.raw",1,3000)
Listening to it also shows up anything nasty:
$ play -s -2 -r 16000 out16_short.raw
$ play -s -2 -r 8000 out8.raw
*/
#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "codec2_fdmdv.h"
#define N8 159 /* procssing buffer size at 8 kHz */
#define N16 (N8 * FDMDV_OS)
#define FRAMES 100
#define TWO_PI 6.283185307
#define FS 16000
#define SINE
int main() {
short in8k_short[FDMDV_OS_TAPS_8K + N8];
short out16k_short[N16];
FILE *f16;
short in16k_short[FDMDV_OS_TAPS_16K + N16];
short out8k_short[N16];
FILE *f8, *f8in;
int i, f, t, t1;
float freq = 800.0;
f16 = fopen("out16_short.raw", "wb");
assert(f16 != NULL);
f8 = fopen("out8_short.raw", "wb");
assert(f8 != NULL);
f8in = fopen("in8_short.raw", "wb");
assert(f8in != NULL);
/* clear filter memories */
for (i = 0; i < FDMDV_OS_TAPS_8K; i++) in8k_short[i] = 0;
for (i = 0; i < FDMDV_OS_TAPS_16K; i++) in16k_short[i] = 0;
t = t1 = 0;
for (f = 0; f < FRAMES; f++) {
#ifdef DC
for (i = 0; i < N8; i++) in8k_short[FDMDV_OS_TAPS_8K + i] = 16000.0;
#endif
#ifdef SINE
for (i = 0; i < N8; i++, t++)
in8k_short[FDMDV_OS_TAPS_8K + i] = 8000.0 * cos(TWO_PI * t * freq / FS);
#endif
fwrite(in8k_short, sizeof(short), N8, f8in);
/* upsample */
fdmdv_8_to_16_short(out16k_short, &in8k_short[FDMDV_OS_TAPS_8K], N8);
fwrite(out16k_short, sizeof(short), N16, f16);
/* add a 6 kHz spurious signal for fun, we want down sampler to
knock this out */
for (i = 0; i < N16; i++, t1++)
in16k_short[i + FDMDV_OS_TAPS_16K] =
out16k_short[i] + 8000.0 * cos(TWO_PI * t1 * 6000.0 / FS);
/* downsample */
fdmdv_16_to_8_short(out8k_short, &in16k_short[FDMDV_OS_TAPS_16K], N8);
/* save 8k to disk for plotting and check out */
fwrite(out8k_short, sizeof(short), N8, f8);
}
fclose(f16);
fclose(f8);
fclose(f8in);
return 0;
}
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