1 /*
2 t16_8_short.c
3 David Rowe
4 19 August 2014
5
6 Unit test for 16 <-> 8 kHz sample rate conversion functions. I
7 evaluated output by plotting using Octave and looking for jaggies:
8
9 pl("../unittest/out16_short.raw",1,3000)
10 pl("../unittest/out8.raw",1,3000)
11
12 Listening to it also shows up anything nasty:
13
14 $ play -s -2 -r 16000 out16_short.raw
15 $ play -s -2 -r 8000 out8.raw
16
17 */
18
19 #include <assert.h>
20 #include <math.h>
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include "codec2_fdmdv.h"
24
25 #define N8 159 /* procssing buffer size at 8 kHz */
26 #define N16 (N8*FDMDV_OS)
27 #define FRAMES 100
28 #define TWO_PI 6.283185307
29 #define FS 16000
30
31 #define SINE
32
main()33 int main() {
34 short in8k_short[FDMDV_OS_TAPS_8K + N8];
35 short out16k_short[N16];
36 FILE *f16;
37
38 short in16k_short[FDMDV_OS_TAPS_16K + N16];
39 short out8k_short[N16];
40 FILE *f8, *f8in;
41
42 int i,f,t,t1;
43 float freq = 800.0;
44
45 f16 = fopen("out16_short.raw", "wb");
46 assert(f16 != NULL);
47 f8 = fopen("out8_short.raw", "wb");
48 assert(f8 != NULL);
49 f8in = fopen("in8_short.raw", "wb");
50 assert(f8in != NULL);
51
52 /* clear filter memories */
53 for(i=0; i<FDMDV_OS_TAPS_8K; i++)
54 in8k_short[i] = 0;
55 for(i=0; i<FDMDV_OS_TAPS_16K; i++)
56 in16k_short[i] = 0;
57
58 t = t1 = 0;
59 for(f=0; f<FRAMES; f++) {
60
61 #ifdef DC
62 for(i=0; i<N8; i++)
63 in8k_short[FDMDV_OS_TAPS_8K+i] = 16000.0;
64 #endif
65 #ifdef SINE
66 for(i=0; i<N8; i++,t++)
67 in8k_short[FDMDV_OS_TAPS_8K+i] = 8000.0*cos(TWO_PI*t*freq/FS);
68 #endif
69 fwrite(in8k_short, sizeof(short), N8, f8in);
70
71 /* upsample */
72 fdmdv_8_to_16_short(out16k_short, &in8k_short[FDMDV_OS_TAPS_8K], N8);
73
74 fwrite(out16k_short, sizeof(short), N16, f16);
75
76 /* add a 6 kHz spurious signal for fun, we want down sampler to
77 knock this out */
78 for(i=0; i<N16; i++,t1++)
79 in16k_short[i+FDMDV_OS_TAPS_16K] = out16k_short[i] + 8000.0*cos(TWO_PI*t1*6000.0/FS);
80
81 /* downsample */
82 fdmdv_16_to_8_short(out8k_short, &in16k_short[FDMDV_OS_TAPS_16K], N8);
83
84 /* save 8k to disk for plotting and check out */
85 fwrite(out8k_short, sizeof(short), N8, f8);
86
87 }
88
89 fclose(f16);
90 fclose(f8);
91 fclose(f8in);
92 return 0;
93
94 }
95