void scanner(void)
{
int i, j, j2, f, n_read, offset, bin_e, bin_len, buf_len, ds, ds_p;
int32_t w;
struct tuning_state *ts;
bin_e = tunes[0].bin_e;
bin_len = 1 << bin_e;
buf_len = tunes[0].buf_len;
for (i=0; i<tune_count; i++) {
if (do_exit >= 2)
{return;}
ts = &tunes[i];
f = (int)rtlsdr_get_center_freq(dev);
if (f != ts->freq) {
retune(dev, ts->freq);}
rtlsdr_read_sync(dev, ts->buf8, buf_len, &n_read);
if (n_read != buf_len) {
fprintf(stderr, "Error: dropped samples.\n");}
/* rms */
if (bin_len == 1) {
rms_power(ts);
continue;
}
/* prep for fft */
for (j=0; j<buf_len; j++) {
fft_buf[j] = (int16_t)ts->buf8[j] - 127;
}
ds = ts->downsample;
ds_p = ts->downsample_passes;
if (boxcar && ds > 1) {
j=2, j2=0;
while (j < buf_len) {
fft_buf[j2] += fft_buf[j];
fft_buf[j2+1] += fft_buf[j+1];
fft_buf[j] = 0;
fft_buf[j+1] = 0;
j += 2;
if (j % (ds*2) == 0) {
j2 += 2;}
}
} else if (ds_p) { /* recursive */
for (j=0; j < ds_p; j++) {
downsample_iq(fft_buf, buf_len >> j);
}
/* droop compensation */
if (comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) {
generic_fir(fft_buf, buf_len >> j, cic_9_tables[ds_p]);
generic_fir(fft_buf+1, (buf_len >> j)-1, cic_9_tables[ds_p]);
}
}
remove_dc(fft_buf, buf_len / ds);
remove_dc(fft_buf+1, (buf_len / ds) - 1);
/* window function and fft */
for (offset=0; offset<(buf_len/ds); offset+=(2*bin_len)) {
// todo, let rect skip this
for (j=0; j<bin_len; j++) {
w = (int32_t)fft_buf[offset+j*2];
w *= (int32_t)(window_coefs[j]);
//w /= (int32_t)(ds);
fft_buf[offset+j*2] = (int16_t)w;
w = (int32_t)fft_buf[offset+j*2+1];
w *= (int32_t)(window_coefs[j]);
//w /= (int32_t)(ds);
fft_buf[offset+j*2+1] = (int16_t)w;
}
fix_fft(fft_buf+offset, bin_e);
if (!peak_hold) {
for (j=0; j<bin_len; j++) {
ts->avg[j] += real_conj(fft_buf[offset+j*2], fft_buf[offset+j*2+1]);
}
} else {
for (j=0; j<bin_len; j++) {
ts->avg[j] = MAX(real_conj(fft_buf[offset+j*2], fft_buf[offset+j*2+1]), ts->avg[j]);
}
}
ts->samples += ds;
}
}
void iqconverter_int16_process(iqconverter_int16_t *cnv, int16_t *samples, int len)
{
remove_dc(cnv, samples, len);
translate_fs_4(cnv, samples, len);
}
