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first pass a config driven Tx BPF set up
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@drowe67
drowe67 committed May 3, 2024
1 parent d026cfe commit cfa9cd0
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Showing 3 changed files with 56 additions and 39 deletions.
51 changes: 21 additions & 30 deletions src/ofdm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -192,6 +192,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
ofdm->codename = "HRA_112_112";
ofdm->amp_est_mode = 0;
ofdm->tx_bpf_en = true;
ofdm->tx_bpf_proto = filtP650S900;
ofdm->tx_bpf_proto_n = sizeof(filtP650S900) / sizeof(float);
ofdm->rx_bpf_en = false;
ofdm->amp_scale = 245E3;
ofdm->clip_gain1 = 2.0;
Expand Down Expand Up @@ -226,6 +228,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
ofdm->codename = config->codename;
ofdm->amp_est_mode = config->amp_est_mode;
ofdm->tx_bpf_en = config->tx_bpf_en;
ofdm->tx_bpf_proto = config->tx_bpf_proto;
ofdm->tx_bpf_proto_n = config->tx_bpf_proto_n;
ofdm->rx_bpf_en = config->rx_bpf_en;
ofdm->foff_limiter = config->foff_limiter;
ofdm->amp_scale = config->amp_scale;
Expand Down Expand Up @@ -275,6 +279,8 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
ofdm->config.codename = ofdm->codename;
ofdm->config.amp_est_mode = ofdm->amp_est_mode;
ofdm->config.tx_bpf_en = ofdm->tx_bpf_en;
ofdm->config.tx_bpf_proto = ofdm->tx_bpf_proto;
ofdm->config.tx_bpf_proto_n = ofdm->tx_bpf_proto_n;
ofdm->config.rx_bpf_en = ofdm->rx_bpf_en;
ofdm->config.foff_limiter = ofdm->foff_limiter;
ofdm->config.amp_scale = ofdm->amp_scale;
Expand Down Expand Up @@ -539,36 +545,19 @@ struct OFDM *ofdm_create(const struct OFDM_CONFIG *config) {
static void allocate_tx_bpf(struct OFDM *ofdm) {
ofdm->tx_bpf = MALLOC(sizeof(struct quisk_cfFilter));
assert(ofdm->tx_bpf != NULL);
assert(ofdm->tx_bpf_proto != NULL);
assert(ofdm->tx_bpf_proto_n != 0);

/* Transmit bandpass filter; complex coefficients, center frequency */

if (!strcmp(ofdm->mode, "700D")) {
quisk_filt_cfInit(ofdm->tx_bpf, filtP650S900,
sizeof(filtP650S900) / sizeof(float));
quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
} else if (!strcmp(ofdm->mode, "700E") || !strcmp(ofdm->mode, "2020") ||
!strcmp(ofdm->mode, "datac1")) {
quisk_filt_cfInit(ofdm->tx_bpf, filtP900S1100,
sizeof(filtP900S1100) / sizeof(float));
quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
} else if (!strcmp(ofdm->mode, "2020B")) {
quisk_filt_cfInit(ofdm->tx_bpf, filtP1100S1300,
sizeof(filtP1100S1300) / sizeof(float));
quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
} else if (!strcmp(ofdm->mode, "datac0") || !strcmp(ofdm->mode, "datac3")) {
quisk_filt_cfInit(ofdm->tx_bpf, filtP400S600,
sizeof(filtP400S600) / sizeof(float));
quisk_cfTune(ofdm->tx_bpf, ofdm->tx_centre / ofdm->fs);
} else if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
!strcmp(ofdm->mode, "datac14")) {
quisk_filt_cfInit(ofdm->tx_bpf, filtP200S400,
sizeof(filtP200S400) / sizeof(float));
// centre the filter on the mean carrier freq, allows a narrower filter to
// be used
float tx_centre = find_carrier_centre(ofdm);
quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs);
} else
assert(0);
quisk_filt_cfInit(ofdm->tx_bpf, ofdm->tx_bpf_proto, ofdm->tx_bpf_proto_n);
float tx_centre = ofdm->tx_centre;
if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
!strcmp(ofdm->mode, "datac14")) {
// Centre the filter on the mean carrier freq, allows a narrower
// filter to be used. Only really useful for very narrow, Nc odd
// waveforms. TODO: make this feature config controlled
tx_centre = find_carrier_centre(ofdm);
}
quisk_cfTune(ofdm->tx_bpf, tx_centre / ofdm->fs);
}

static void deallocate_tx_bpf(struct OFDM *ofdm) {
Expand All @@ -589,7 +578,9 @@ static void allocate_rx_bpf(struct OFDM *ofdm) {
ofdm->rx_bpf = MALLOC(sizeof(struct quisk_cfFilter));
assert(ofdm->rx_bpf != NULL);

/* Receive bandpass filter; complex coefficients, center frequency */
/* Receive bandpass filter; complex coefficients, center frequency, only
really needed for very low SNR waveforms. TODO: make this config
controlled. */

if (!strcmp(ofdm->mode, "datac4") || !strcmp(ofdm->mode, "datac13") ||
!strcmp(ofdm->mode, "datac14")) {
Expand Down
22 changes: 13 additions & 9 deletions src/ofdm_internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -94,15 +94,17 @@ struct OFDM_CONFIG {
char *codename; /* name of LDPC code used with this mode */
uint8_t tx_uw[MAX_UW_BITS]; /* user defined unique word */
int amp_est_mode;
bool tx_bpf_en; /* default tx (mod) hilbert clipper BPF enable */
bool rx_bpf_en; /* default rx (demod) input BPF enable */
bool foff_limiter; /* tames freq offset updates in low SNR */
float amp_scale; /* used to scale Tx waveform to approx FREEDV_PEAK with
clipper off */
float clip_gain1; /* gain we apply to Tx signal before clipping to control
PAPR*/
float clip_gain2; /* gain we apply to Tx signal after clipping and BBF to
control peak level */
bool tx_bpf_en; /* default tx (mod) hilbert clipper BPF enable */
bool rx_bpf_en; /* default rx (demod) input BPF enable */
float *tx_bpf_proto; /* low pass prototype for complex BPF */
int tx_bpf_proto_n; /* number of taps in low pass prototype */
bool foff_limiter; /* tames freq offset updates in low SNR */
float amp_scale; /* used to scale Tx waveform to approx FREEDV_PEAK with
clipper off */
float clip_gain1; /* gain we apply to Tx signal before clipping to control
PAPR*/
float clip_gain2; /* gain we apply to Tx signal after clipping and BBF to
control peak level */
bool clip_en;
char mode[16]; /* OFDM mode in string form */
char *data_mode;
Expand Down Expand Up @@ -156,6 +158,7 @@ struct OFDM {
int packetsperburst; /* for OFDM data modes, how many packets before we reset
state machine */
int amp_est_mode; /* amplitude estimtor algorithm */
int tx_bpf_proto_n; /* number of taps in low pass prototype */
float amp_scale;
float clip_gain1;
float clip_gain2;
Expand Down Expand Up @@ -220,6 +223,7 @@ struct OFDM {
float coarse_foff_est_hz;
float timing_norm;
float mean_amp;
float *tx_bpf_proto;

// Integer
int clock_offset_counter;
Expand Down
22 changes: 22 additions & 0 deletions src/ofdm_mode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->clip_gain2 = 0.8;
config->clip_en = true;
config->tx_bpf_en = true;
config->tx_bpf_proto = filtP650S900;
config->tx_bpf_proto_n = sizeof(filtP650S900) / sizeof(float);
config->rx_bpf_en = false;
config->amp_scale = 245E3;
config->foff_limiter = false;
Expand All @@ -69,13 +71,17 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->amp_scale = 155E3;
config->clip_gain1 = 3;
config->clip_gain2 = 0.8;
config->tx_bpf_proto = filtP900S1100;
config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
} else if ((strcmp(mode, "2020") == 0)) {
config->ts = 0.0205;
config->nc = 31;
config->codename = "HRAb_396_504";
config->amp_scale = 167E3;
config->clip_gain1 = 2.5;
config->clip_gain2 = 0.8;
config->tx_bpf_proto = filtP900S1100;
config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
} else if (strcmp(mode, "2020B") == 0) {
config->ts = 0.014;
config->tcp = 0.004;
Expand All @@ -92,6 +98,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->state_machine = "voice2";
config->ftwindowwidth = 64;
config->foff_limiter = true;
config->tx_bpf_proto = filtP1100S1300;
config->tx_bpf_proto_n = sizeof(filtP1100S1300) / sizeof(float);
} else if (strcmp(mode, "qam16") == 0) {
/* not in use yet */
config->ns = 5;
Expand All @@ -109,6 +117,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->tx_bpf_en = false;
config->clip_en = false;
config->data_mode = "streaming";
config->tx_bpf_proto = NULL;
config->tx_bpf_proto_n = 0;
} else if (strcmp(mode, "datac0") == 0) {
config->ns = 5;
config->np = 4;
Expand All @@ -130,6 +140,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->amp_scale = 300E3;
config->clip_gain1 = 2.2;
config->clip_gain2 = 0.85;
config->tx_bpf_proto = filtP400S600;
config->tx_bpf_proto_n = sizeof(filtP400S600) / sizeof(float);
} else if (strcmp(mode, "datac1") == 0) {
config->ns = 5;
config->np = 38;
Expand All @@ -152,6 +164,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->amp_scale = 145E3;
config->clip_gain1 = 2.7;
config->clip_gain2 = 0.8;
config->tx_bpf_proto = filtP900S1100;
config->tx_bpf_proto_n = sizeof(filtP900S1100) / sizeof(float);
} else if (strcmp(mode, "datac3") == 0) {
config->ns = 5;
config->np = 29;
Expand All @@ -176,6 +190,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->amp_scale = 300E3;
config->clip_gain1 = 2.2;
config->clip_gain2 = 0.8;
config->tx_bpf_proto = filtP400S600;
config->tx_bpf_proto_n = sizeof(filtP400S600) / sizeof(float);
} else if (strcmp(mode, "datac4") == 0) {
config->ns = 5;
config->np = 47;
Expand All @@ -201,6 +217,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->clip_gain1 = 1.2;
config->clip_gain2 = 1.0;
config->rx_bpf_en = true;
config->tx_bpf_proto = filtP200S400;
config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
} else if (strcmp(mode, "datac13") == 0) {
config->ns = 5;
config->np = 18;
Expand All @@ -226,6 +244,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->clip_gain1 = 1.2;
config->clip_gain2 = 1.0;
config->rx_bpf_en = true;
config->tx_bpf_proto = filtP200S400;
config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
} else if (strcmp(mode, "datac14") == 0) {
config->ns = 5;
config->np = 4;
Expand All @@ -251,6 +271,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
config->clip_gain1 = 2.0;
config->clip_gain2 = 1.0;
config->rx_bpf_en = true;
config->tx_bpf_proto = filtP200S400;
config->tx_bpf_proto_n = sizeof(filtP200S400) / sizeof(float);
} else {
assert(0);
}
Expand Down

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