Transceivert52M: Add option for baseband frequency offset

Allow command line setting of the DSP frequency in UHD. All channels
will be tuned with the same offset. Dual-channel tuning with the B210,
which uses a single LO, will override the command line offset value
and set the DSP frequency automatically.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

Transceiver52M/UHDDevice.cpp

@@ -257,7 +257,7 @@ private:
 */
 class uhd_device : public RadioDevice {
 public:
-	uhd_device(size_t sps, size_t chans, bool diversity);
+	uhd_device(size_t sps, size_t chans, bool diversity, double offset);
 	~uhd_device();
 
 	int open(const std::string &args, bool extref);
@@ -324,6 +324,7 @@ private:
 
 	double tx_gain_min, tx_gain_max;
 	double rx_gain_min, rx_gain_max;
+	double offset;
 
 	std::vector<double> tx_gains, rx_gains;
 	std::vector<double> tx_freqs, rx_freqs;
@@ -390,7 +391,7 @@ void uhd_msg_handler(uhd::msg::type_t type, const std::string &msg)
 	}
 }
 
-uhd_device::uhd_device(size_t sps, size_t chans, bool diversity)
+uhd_device::uhd_device(size_t sps, size_t chans, bool diversity, double offset)
 	: tx_gain_min(0.0), tx_gain_max(0.0),
 	  rx_gain_min(0.0), rx_gain_max(0.0),
 	  tx_spp(0), rx_spp(0),
@@ -399,6 +400,7 @@ uhd_device::uhd_device(size_t sps, size_t chans, bool diversity)
 {
 	this->sps = sps;
 	this->chans = chans;
+	this->offset = offset;
 	this->diversity = diversity;
 }
 
@@ -980,11 +982,12 @@ uhd::tune_request_t uhd_device::select_freq(double freq, size_t chan, bool tx)
 	std::vector<double> freqs;
 	uhd::tune_request_t treq(freq);
 
-	if (chans == 1)
-		return treq;
-	else if ((dev_type == UMTRX) && (chans == 2))
-		return treq;
-	else if ((dev_type != B210) || (chans > 2) || (chan > 1)) {
+	if ((chans == 1) || ((chans == 2) && dev_type == UMTRX)) {
+		if (offset == 0.0)
+			return treq;
+
+		return uhd::tune_request_t(freq, offset);
+	} else if ((dev_type != B210) || (chans > 2) || (chan > 1)) {
 		LOG(ALERT) << chans << " channels unsupported";
 		return treq;
 	}
@@ -1029,6 +1032,9 @@ bool uhd_device::set_freq(double freq, size_t chan, bool tx)
 	}
 	LOG(INFO) << "\n" << tres.to_pp_string() << std::endl;
 
+	if ((chans == 1) || ((chans == 2) && dev_type == UMTRX))
+		return true;
+
 	/* Manual RF policy means we intentionally tuned with a baseband
 	 * offset for dual-channel purposes. Now retune the other channel
 	 * with the opposite corresponding frequency offset
@@ -1324,7 +1330,8 @@ std::string smpl_buf::str_code(ssize_t code)
 	}
 }
 
-RadioDevice *RadioDevice::make(size_t sps, size_t chans, bool diversity)
+RadioDevice *RadioDevice::make(size_t sps, size_t chans,
+			       bool diversity, double offset)
 {
-	return new uhd_device(sps, chans, diversity);
+	return new uhd_device(sps, chans, diversity, offset);
 }

Transceiver52M/osmo-trx.cpp

@@ -68,6 +68,7 @@ struct trx_config {
 	bool extref;
 	bool filler;
 	bool diversity;
+	double offset;
 };
 
 ConfigurationTable gConfig;
@@ -178,6 +179,7 @@ bool trx_setup_config(struct trx_config *config)
 	ost << "   External Reference...... " << refstr << std::endl;
 	ost << "   C0 Filler Table......... " << fillstr << std::endl;
 	ost << "   Diversity............... " << divstr << std::endl;
+	ost << "   Tuning offset........... " << config->offset << std::endl;
 	std::cout << ost << std::endl;
 
 	return true;
@@ -283,7 +285,8 @@ static void print_help()
 		"  -x    Enable external 10 MHz reference\n"
 		"  -s    Samples-per-symbol (1 or 4)\n"
 		"  -c    Number of ARFCN channels (default=1)\n"
-		"  -f    Enable C0 filler table\n",
+		"  -f    Enable C0 filler table\n"
+		"  -o    Set baseband frequency offset (default=auto)\n",
 		"EMERG, ALERT, CRT, ERR, WARNING, NOTICE, INFO, DEBUG");
 }
 
@@ -297,8 +300,9 @@ static void handle_options(int argc, char **argv, struct trx_config *config)
 	config->extref = false;
 	config->filler = false;
 	config->diversity = false;
+	config->offset = 0.0;
 
-	while ((option = getopt(argc, argv, "ha:l:i:p:c:dxfs:")) != -1) {
+	while ((option = getopt(argc, argv, "ha:l:i:p:c:dxfo:s:")) != -1) {
 		switch (option) {
 		case 'h':
 			print_help();
@@ -328,6 +332,9 @@ static void handle_options(int argc, char **argv, struct trx_config *config)
 		case 'f':
 			config->filler = true;
 			break;
+		case 'o':
+			config->offset = atof(optarg);
+			break;
 		case 's':
 			config->sps = atoi(optarg);
 			if ((config->sps != 1) && (config->sps != 4)) {
@@ -366,7 +373,8 @@ int main(int argc, char *argv[])
 	srandom(time(NULL));
 
 	/* Create the low level device object */
-	usrp = RadioDevice::make(config.sps, config.chans, config.diversity);
+	usrp = RadioDevice::make(config.sps, config.chans,
+				 config.diversity, config.offset);
 	type = usrp->open(config.dev_args, config.extref);
 	if (type < 0) {
 		LOG(ALERT) << "Failed to create radio device" << std::endl;

Transceiver52M/radioDevice.h

@@ -38,7 +38,7 @@ class RadioDevice {
   enum RadioInterfaceType { NORMAL, RESAMP_64M, RESAMP_100M, DIVERSITY };
 
   static RadioDevice *make(size_t sps, size_t chans = 1,
-                           bool diversity = false);
+                           bool diversity = false, double offset = 0.0);
 
   /** Initialize the USRP */
   virtual int open(const std::string &args = "", bool extref = false)=0;