static void test_line_filter(int line_model_no)
{
float out;
double sumin;
double sumout;
double gain;
int i;
int j;
int p;
int ptr;
int len;
swept_tone_state_t *s;
float filter[129];
int16_t buf[BLOCK_LEN];
s = swept_tone_init(NULL, 200.0f, 3900.0f, -10.0f, 120*SAMPLE_RATE, 0);
for (j = 0; j < 129; j++)
filter[j] = 0.0f;
ptr = 0;
for (;;)
{
if ((len = swept_tone(s, buf, BLOCK_LEN)) <= 0)
break;
sumin = 0.0;
sumout = 0.0;
for (i = 0; i < len; i++)
{
/* Add the sample in the filter buffer */
p = ptr;
filter[p] = buf[i];
if (++p == 129)
p = 0;
ptr = p;
/* Apply the filter */
out = 0.0f;
for (j = 0; j < 129; j++)
{
out += line_models[line_model_no][128 - j]*filter[p];
if (++p >= 129)
p = 0;
}
sumin += buf[i]*buf[i];
sumout += out*out;
}
/*endfor*/
gain = (sumin != 0.0) ? 10.0*log10(sumout/sumin + 1.0e-10) : 0.0;
printf("%7.1f %f\n", swept_tone_current_frequency(s), gain);
}
/*endfor*/
swept_tone_free(s);
}
int16_t buf[SAMPLES_PER_CHUNK];
int i;
int len;
double sumin;
double sumout;
swept_tone_state_t *swept;
double freq;
double gain;
int template_entry;
FILE *file;
/* Things like noise don't highlight the frequency response of the high Q notch
very well. We use a slowly swept frequency to check it. */
printf("Frequency response test\n");
sig_tone_rx_set_mode(s, SIG_TONE_RX_PASSTHROUGH | SIG_TONE_RX_FILTER_TONE, 0);
swept = swept_tone_init(NULL, 200.0f, 3900.0f, -10.0f, 120*SAMPLE_RATE, 0);
template_entry = 0;
file = fopen("sig_tone_notch", "wb");
for (;;)
{
if ((len = swept_tone(swept, buf, SAMPLES_PER_CHUNK)) <= 0)
break;
/*endif*/
sumin = 0.0;
for (i = 0; i < len; i++)
sumin += (double) buf[i]*(double) buf[i];
/*endfor*/
sig_tone_rx(s, buf, len);
sumout = 0.0;
for (i = 0; i < len; i++)
sumout += (double) buf[i]*(double) buf[i];
