kopia lustrzana https://github.com/rs1729/RS
iq_fm: little speedup, manual FM gain, RF64, FM dec
Zilog80
rodzic
ebac1c4a9b
commit
6d1f4f162e
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@ -30,7 +30,11 @@
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#define M_PI (3.1415926535897932384626433832795)
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#endif
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#define LP_IQ 1
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#define LP_FM 2
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#define FM_GAIN (0.8)
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float fm_gain = FM_GAIN;
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typedef unsigned char ui8_t;
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@ -52,6 +56,8 @@ typedef struct {
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ui32_t sample;
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int opt_lp;
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// IF: lowpass
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int lpIQ_bw;
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float lpIQ_fbw;
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@ -59,11 +65,21 @@ typedef struct {
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float *ws_lpIQ;
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float complex *lpIQ_buf;
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// FM: lowpass
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int lpFM_bw;
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int lpFMtaps; // ui32_t
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float *ws_lpFM;
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float *lpFM_buf;
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float *fm_buffer;
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int decFM;
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} dsp_t;
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typedef struct {
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int sr; // sample_rate
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int sr_out;
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int bps; // bits_sample bits/sample
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int nch; // channels
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int bps_out;
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@ -79,7 +95,7 @@ static int findstr(char *buff, char *str, int pos) {
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return i;
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}
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static float read_wav_header(pcm_t *pcm) {
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static int read_wav_header(pcm_t *pcm) {
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FILE *fp = pcm->fp;
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char txt[4+1] = "\0\0\0\0";
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unsigned char dat[4];
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@ -87,11 +103,13 @@ static float read_wav_header(pcm_t *pcm) {
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int sample_rate = 0, bits_sample = 0, channels = 0;
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if (fread(txt, 1, 4, fp) < 4) return -1;
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if (strncmp(txt, "RIFF", 4)) return -1;
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if (strncmp(txt, "RIFF", 4) && strncmp(txt, "RF64", 4)) return -1;
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if (fread(txt, 1, 4, fp) < 4) return -1;
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// pos_WAVE = 8L
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if (fread(txt, 1, 4, fp) < 4) return -1;
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if (strncmp(txt, "WAVE", 4)) return -1;
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// pos_fmt = 12L
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for ( ; ; ) {
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if ( (byte=fgetc(fp)) == EOF ) return -1;
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@ -142,7 +160,7 @@ static float read_wav_header(pcm_t *pcm) {
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static float write_wav_header(pcm_t *pcm) {
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FILE *fp = stdout;
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ui32_t sr = pcm->sr;
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ui32_t sr = pcm->sr_out;
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ui32_t bps = pcm->bps_out;
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ui32_t data = 0;
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@ -255,14 +273,6 @@ static int lowpass_init(float f, int taps, float **pws) {
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return taps;
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}
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static float complex lowpass0(float complex buffer[], ui32_t sample, ui32_t taps, float *ws) {
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ui32_t n;
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double complex w = 0;
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for (n = 0; n < taps; n++) {
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w += buffer[(sample+n+1)%taps]*ws[taps-1-n];
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}
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return (float complex)w;
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}
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static float complex lowpass(float complex buffer[], ui32_t sample, ui32_t taps, float *ws) {
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ui32_t n;
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ui32_t s = sample % taps;
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@ -274,9 +284,20 @@ static float complex lowpass(float complex buffer[], ui32_t sample, ui32_t taps,
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// symmetry: ws[n] == ws[taps-1-n]
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}
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static float re_lowpass(float buffer[], ui32_t sample, ui32_t taps, float *ws) {
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ui32_t n;
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ui32_t s = sample % taps;
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double w = 0;
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for (n = 0; n < taps; n++) {
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w += buffer[n]*ws[taps+s-n]; // ws[taps+s-n] = ws[(taps+sample-n)%taps]
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}
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return (float)w;
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}
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/* -------------------------------------------------------------------------- */
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#define IF_TRANSITION_BW (4e3) // 4kHz transition width
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#define FM_TRANSITION_BW (4e3) // (min) transition width
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static int init_buffers(dsp_t *dsp) {
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@ -294,6 +315,32 @@ static int init_buffers(dsp_t *dsp) {
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dsp->lpIQ_buf = calloc( dsp->lpIQtaps+3, sizeof(float complex));
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if (dsp->lpIQ_buf == NULL) return -1;
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// FM lowpass
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if (dsp->opt_lp & LP_FM)
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{
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float f_lp; // lowpass_bw
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int taps; // lowpass taps: 4*sr/transition_bw
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f_lp = 4e3/(float)dsp->sr; // default
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if (dsp->lpFM_bw > 0) f_lp = dsp->lpFM_bw/(float)dsp->sr;
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taps = 4*dsp->sr/FM_TRANSITION_BW;
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if (dsp->decFM > 1)
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{
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f_lp *= 2; //if (dsp->opt_iq >= 2 && dsp->opt_iq < 6) f_lp *= 2;
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taps = taps/2;
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}
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if (dsp->sr > 100e3) taps = taps/2;
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if (dsp->sr > 200e3) taps = taps/2;
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//if (dsp->opt_iq == 5) taps = taps/2;
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if (taps%2==0) taps++;
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taps = lowpass_init(f_lp, taps, &dsp->ws_lpFM); if (taps < 0) return -1;
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dsp->lpFMtaps = taps;
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dsp->lpFM_buf = calloc( dsp->lpFMtaps+3, sizeof(float));
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if (dsp->lpFM_buf == NULL) return -1;
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}
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return 0;
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}
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@ -302,33 +349,58 @@ static int free_buffers(dsp_t *dsp) {
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if (dsp->lpIQ_buf) { free(dsp->lpIQ_buf); dsp->lpIQ_buf = NULL; }
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if (dsp->ws_lpIQ) { free(dsp->ws_lpIQ); dsp->ws_lpIQ = NULL; }
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// FM lowpass
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if (dsp->opt_lp & LP_FM)
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{
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if (dsp->ws_lpFM) { free(dsp->ws_lpFM); dsp->ws_lpFM = NULL; }
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if (dsp->lpFM_buf) { free(dsp->lpFM_buf); dsp->lpFM_buf = NULL; }
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}
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return 0;
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}
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/* -------------------------------------------------------------------------- */
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static int fm_demod(dsp_t *dsp, float *s) {
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double gain = FM_GAIN;
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float complex z, z1, w;
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static float complex z0;
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float complex z, z1, w;
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float s_fm;
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float gain = fm_gain;
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ui32_t _sample = dsp->sample * dsp->decFM;
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int m;
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if ( f32read_csample(dsp, &z) == EOF ) return EOF;
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for (m = 0; m < dsp->decFM; m++)
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{
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dsp->lpIQ_buf[dsp->sample % dsp->lpIQtaps] = z;
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z1 = lowpass(dsp->lpIQ_buf, dsp->sample, dsp->lpIQtaps, dsp->ws_lpIQ);
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if ( f32read_csample(dsp, &z) == EOF ) return EOF;
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w = z1 * conj(z0);
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*s = gain * carg(w)/M_PI;
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dsp->lpIQ_buf[_sample % dsp->lpIQtaps] = z;
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z1 = lowpass(dsp->lpIQ_buf, _sample, dsp->lpIQtaps, dsp->ws_lpIQ);
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z0 = z1;
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w = z1 * conj(z0);
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s_fm = gain * carg(w)/M_PI;
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z0 = z1;
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// FM-lowpass
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if (dsp->opt_lp & LP_FM) {
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dsp->lpFM_buf[_sample % dsp->lpFMtaps] = s_fm;
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if (m+1 == dsp->decFM) {
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s_fm = re_lowpass(dsp->lpFM_buf, _sample, dsp->lpFMtaps, dsp->ws_lpFM);
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}
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}
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_sample += 1;
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}
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*s = s_fm;
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dsp->sample += 1;
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return 0;
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}
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static int write_fm(dsp_t *dsp, float s) {
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static int fwrite_fm(dsp_t *dsp, float s) {
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int bps = dsp->bps_out;
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FILE *fpo = stdout;
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ui8_t u = 0;
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@ -357,6 +429,8 @@ int main(int argc, char *argv[]) {
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int k;
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int option_pcmraw = 0;
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int option_wav = 0;
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int option_lp = 0;
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int option_decFM = 0;
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int file_loaded = 0;
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int bitQ = 0;
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@ -378,7 +452,19 @@ int main(int argc, char *argv[]) {
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++argv;
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if (*argv) bw = atof(*argv);
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else return 1;
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if (bw > 4.6 && bw < 24.0) lpIQ_bw = bw*1e3;
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if (bw > 2.0) lpIQ_bw = bw*1e3;
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}
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else if (strcmp(*argv, "--lpFM") == 0) { option_lp |= LP_FM; } // FM lowpass
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else if (strcmp(*argv, "--decFM") == 0) { // FM decimation
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option_decFM = 4;
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option_lp |= LP_FM;
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}
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else if (strcmp(*argv, "-g") == 0) { // FM gain (default: 0.8)
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double _g = 0.0;
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++argv;
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if (*argv) _g = atof(*argv);
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else return 1;
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if (_g > 0) fm_gain = _g;
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}
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else if (strcmp(*argv, "-") == 0) {
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int sample_rate = 0, bits_sample = 0, channels = 0;
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@ -436,24 +522,38 @@ int main(int argc, char *argv[]) {
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if (pcm.bps_out == 0) pcm.bps_out = pcm.bps;
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if (option_wav) write_wav_header( &pcm );
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dsp.fp = fp;
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dsp.sr = pcm.sr;
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dsp.bps = pcm.bps;
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dsp.nch = pcm.nch;
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dsp.bps_out = pcm.bps_out;
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if (lpIQ_bw > pcm.sr) lpIQ_bw = pcm.sr;
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dsp.lpIQ_bw = lpIQ_bw; // IF lowpass bandwidth
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dsp.decFM = 1;
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if (option_decFM) {
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int fm_sr = dsp.sr;
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while (fm_sr % 2 == 0 && fm_sr/2 >= 48000) {
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fm_sr /= 2;
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dsp.decFM *= 2;
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}
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//option_lp |= LP_FM;
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}
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dsp.opt_lp = option_lp;
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init_buffers(&dsp);
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pcm.sr_out = pcm.sr / dsp.decFM;
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if (option_wav) write_wav_header( &pcm );
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while ( 1 )
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{
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bitQ = fm_demod(&dsp, &s);
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if ( bitQ == EOF ) break;
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write_fm(&dsp, s);
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fwrite_fm(&dsp, s);
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}
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