Add support for SoapySDR

7 files changed, 546 insertions, 52 deletions

diff --git a/src/DabMod.cpp b/src/DabMod.cpp
index 44951d7..9cb25a3 100644
--- a/src/DabMod.cpp
+++ b/src/DabMod.cpp
@@ -39,6 +39,9 @@
 #if defined(HAVE_OUTPUT_UHD)
 #   include "OutputUHD.h"
 #endif
+#if defined(HAVE_SOAPYSDR)
+#   include "OutputSoapy.h"
+#endif
 #include "OutputZeroMQ.h"
 #include "InputReader.h"
 #include "PcDebug.h"
@@ -140,6 +143,7 @@ int launch_modulator(int argc, char* argv[])
     int useFileOutput = 0;
     std::string fileOutputFormat = "complexf";
     int useUHDOutput = 0;
+    int useSoapyOutput = 0;
 
     size_t outputRate = 2048000;
     size_t clockRate = 0;
@@ -171,6 +175,10 @@ int launch_modulator(int argc, char* argv[])
     OutputUHDConfig outputuhd_conf;
 #endif
 
+#if defined(HAVE_SOAPYSDR)
+    OutputSoapyConfig outputsoapy_conf;
+#endif
+
     modulator_data m;
 
     // To handle the timestamp offset of the modulator
@@ -312,6 +320,9 @@ int launch_modulator(int argc, char* argv[])
 #if defined(HAVE_OUTPUT_UHD)
         "output_uhd " <<
 #endif
+#if defined(HAVE_SOAPYSDR)
+        "output_soapysdr " <<
+#endif
 #if defined(__FAST_MATH__)
         "fast-math" <<
 #endif
@@ -485,50 +496,7 @@ int launch_modulator(int argc, char* argv[])
                 throw std::runtime_error("Configuration error");
             }
             else if (outputuhd_conf.frequency == 0) {
-                double freq;
-                if      (chan == "5A") freq = 174928000;
-                else if (chan == "5B") freq = 176640000;
-                else if (chan == "5C") freq = 178352000;
-                else if (chan == "5D") freq = 180064000;
-                else if (chan == "6A") freq = 181936000;
-                else if (chan == "6B") freq = 183648000;
-                else if (chan == "6C") freq = 185360000;
-                else if (chan == "6D") freq = 187072000;
-                else if (chan == "7A") freq = 188928000;
-                else if (chan == "7B") freq = 190640000;
-                else if (chan == "7C") freq = 192352000;
-                else if (chan == "7D") freq = 194064000;
-                else if (chan == "8A") freq = 195936000;
-                else if (chan == "8B") freq = 197648000;
-                else if (chan == "8C") freq = 199360000;
-                else if (chan == "8D") freq = 201072000;
-                else if (chan == "9A") freq = 202928000;
-                else if (chan == "9B") freq = 204640000;
-                else if (chan == "9C") freq = 206352000;
-                else if (chan == "9D") freq = 208064000;
-                else if (chan == "10A") freq = 209936000;
-                else if (chan == "10B") freq = 211648000;
-                else if (chan == "10C") freq = 213360000;
-                else if (chan == "10D") freq = 215072000;
-                else if (chan == "11A") freq = 216928000;
-                else if (chan == "11B") freq = 218640000;
-                else if (chan == "11C") freq = 220352000;
-                else if (chan == "11D") freq = 222064000;
-                else if (chan == "12A") freq = 223936000;
-                else if (chan == "12B") freq = 225648000;
-                else if (chan == "12C") freq = 227360000;
-                else if (chan == "12D") freq = 229072000;
-                else if (chan == "13A") freq = 230784000;
-                else if (chan == "13B") freq = 232496000;
-                else if (chan == "13C") freq = 234208000;
-                else if (chan == "13D") freq = 235776000;
-                else if (chan == "13E") freq = 237488000;
-                else if (chan == "13F") freq = 239200000;
-                else {
-                    std::cerr << "       UHD output: channel " << chan << " does not exist in table\n";
-                    throw std::out_of_range("UHD channel selection error");
-                }
-                outputuhd_conf.frequency = freq;
+                outputuhd_conf.frequency = parseChannel(chan);
             }
             else if (outputuhd_conf.frequency != 0 && chan != "") {
                 std::cerr << "       UHD output: cannot define both frequency and channel.\n";
@@ -558,6 +526,31 @@ int launch_modulator(int argc, char* argv[])
             useUHDOutput = 1;
         }
 #endif
+#if defined(HAVE_SOAPYSDR)
+        else if (output_selected == "soapysdr") {
+            outputsoapy_conf.device = pt.get("soapyoutput.device", "");
+            outputsoapy_conf.masterClockRate = pt.get<long>("soapyoutput.master_clock_rate", 0);
+
+            outputsoapy_conf.txgain = pt.get("soapyoutput.txgain", 0.0);
+            outputsoapy_conf.frequency = pt.get<double>("soapyoutput.frequency", 0);
+            std::string chan = pt.get<std::string>("soapyoutput.channel", "");
+            outputsoapy_conf.dabMode = dabMode;
+
+            if (outputsoapy_conf.frequency == 0 && chan == "") {
+                std::cerr << "       soapy output enabled, but neither frequency nor channel defined.\n";
+                throw std::runtime_error("Configuration error");
+            }
+            else if (outputsoapy_conf.frequency == 0) {
+                outputsoapy_conf.frequency =  parseChannel(chan);
+            }
+            else if (outputsoapy_conf.frequency != 0 && chan != "") {
+                std::cerr << "       soapy output: cannot define both frequency and channel.\n";
+                throw std::runtime_error("Configuration error");
+            }
+
+            useSoapyOutput = 1;
+        }
+#endif
 #if defined(HAVE_ZEROMQ)
         else if (output_selected == "zmq") {
             outputName = pt.get<std::string>("zmqoutput.listen");
@@ -649,7 +642,7 @@ int launch_modulator(int argc, char* argv[])
         throw std::invalid_argument("Invalid command line options");
     }
 
-    if (!useFileOutput && !useUHDOutput && !useZeroMQOutput) {
+    if (!useFileOutput && !useUHDOutput && !useZeroMQOutput && !useSoapyOutput) {
         etiLog.level(error) << "Output not specified";
         fprintf(stderr, "Must specify output !");
         throw std::runtime_error("Configuration error");
@@ -679,6 +672,15 @@ int launch_modulator(int argc, char* argv[])
                 outputuhd_conf.pps_src.c_str());
     }
 #endif
+#if defined(HAVE_SOAPYSDR)
+    else if (useSoapyOutput) {
+        fprintf(stderr, " SoapySDR\n"
+                        "  Device: %s\n"
+                        "  master_clock_rate: %ld\n",
+                outputsoapy_conf.device.c_str(),
+                outputsoapy_conf.masterClockRate);
+    }
+#endif
     else if (useZeroMQOutput) {
         fprintf(stderr, " ZeroMQ\n"
                         "  Listening on: %s\n"
@@ -763,6 +765,15 @@ int launch_modulator(int argc, char* argv[])
         rcs.enrol((OutputUHD*)output.get());
     }
 #endif
+#if defined(HAVE_SOAPYSDR)
+    else if (useSoapyOutput) {
+        /* We normalise the same way as for the UHD output */
+        normalise = 1.0f / normalise_factor;
+        outputsoapy_conf.sampleRate = outputRate;
+        output = make_shared<OutputSoapy>(outputsoapy_conf);
+        rcs.enrol((OutputSoapy*)output.get());
+    }
+#endif
 #if defined(HAVE_ZEROMQ)
     else if (useZeroMQOutput) {
         /* We normalise the same way as for the UHD output */
@@ -812,6 +823,11 @@ int launch_modulator(int argc, char* argv[])
             ((OutputUHD*)output.get())->setETISource(modulator->getEtiSource());
         }
 #endif
+#if defined(HAVE_SOAPYSDR)
+        if (useSoapyOutput) {
+            ((OutputSoapy*)output.get())->setETISource(modulator->getEtiSource());
+        }
+#endif
 
         size_t framecount = 0;
 
@@ -863,6 +879,11 @@ int launch_modulator(int argc, char* argv[])
                 ((OutputUHD*)output.get())->setETISource(modulator->getEtiSource());
             }
 #endif
+#if defined(HAVE_SOAPYSDR)
+            if (useSoapyOutput) {
+                ((OutputSoapy*)output.get())->setETISource(modulator->getEtiSource());
+            }
+#endif
 
             m.inputReader->PrintInfo();
 
diff --git a/src/OutputSoapy.cpp b/src/OutputSoapy.cpp
new file mode 100644
index 0000000..3f8db88
--- /dev/null
+++ b/src/OutputSoapy.cpp
@@ -0,0 +1,287 @@
+/*
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Her Majesty the
+   Queen in Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2017
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://opendigitalradio.org
+
+DESCRIPTION:
+   It is an output driver using the SoapySDR library that can output to
+   many devices.
+*/
+
+/*
+   This file is part of ODR-DabMod.
+
+   ODR-DabMod is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of the
+   License, or (at your option) any later version.
+
+   ODR-DabMod is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with ODR-DabMod.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "OutputSoapy.h"
+#ifdef HAVE_SOAPYSDR
+
+#include <SoapySDR/Errors.hpp>
+#include <deque>
+#include <chrono>
+
+#include "Log.h"
+#include "Utils.h"
+
+#include <stdio.h>
+
+static const size_t FRAMES_MAX_SIZE = 2;
+
+
+using namespace std;
+
+
+
+OutputSoapy::OutputSoapy(OutputSoapyConfig& config) :
+    ModOutput(),
+    RemoteControllable("soapy"),
+    m_conf(config),
+    m_device(nullptr)
+{
+    RC_ADD_PARAMETER(txgain, "SoapySDR analog daughterboard TX gain");
+    RC_ADD_PARAMETER(freq,   "SoapySDR transmission frequency");
+    RC_ADD_PARAMETER(overflows, "SoapySDR overflow count [r/o]");
+    RC_ADD_PARAMETER(underflows, "SoapySDR underflow count [r/o]");
+
+    etiLog.level(info) <<
+        "OutputSoapy:Creating the device with: " <<
+        config.device;
+    try
+    {
+        m_device = SoapySDR::Device::make(config.device);
+        stringstream ss;
+        ss << "SoapySDR driver=" << m_device->getDriverKey();
+        ss << " hardware=" << m_device->getHardwareKey();
+        for (const auto &it : m_device->getHardwareInfo())
+        {
+            ss << "  " << it.first << "=" << it.second;
+        }
+    }
+    catch (const std::exception &ex)
+    {
+        etiLog.level(error) << "Error making SoapySDR device: " <<
+            ex.what();
+        throw std::runtime_error("Cannot create SoapySDR output");
+    }
+
+    m_device->setMasterClockRate(config.masterClockRate);
+    etiLog.level(info) << "SoapySDR master clock rate set to " <<
+        m_device->getMasterClockRate()/1000.0 << " kHz";
+
+    m_device->setSampleRate(SOAPY_SDR_TX, 0, m_conf.sampleRate);
+    etiLog.level(info) << "OutputSoapySDR:Actual TX rate: " <<
+        m_device->getSampleRate(SOAPY_SDR_TX, 0) / 1000.0 <<
+        " ksps.";
+
+    m_device->setFrequency(SOAPY_SDR_TX, 0, m_conf.frequency);
+    m_conf.frequency = m_device->getFrequency(SOAPY_SDR_TX, 0);
+    etiLog.level(info) << "OutputSoapySDR:Actual frequency: " <<
+        m_conf.frequency / 1000.0 <<
+        " kHz.";
+
+    m_device->setGain(SOAPY_SDR_TX, 0, m_conf.txgain);
+    etiLog.level(info) << "OutputSoapySDR:Actual tx gain: " <<
+        m_device->getGain(SOAPY_SDR_TX, 0);
+
+}
+
+OutputSoapy::~OutputSoapy()
+{
+    m_worker.stop();
+    if (m_device != nullptr) {
+        SoapySDR::Device::unmake(m_device);
+    }
+}
+
+void SoapyWorker::stop()
+{
+    running = false;
+    queue.push({});
+    if (m_thread.joinable()) {
+        m_thread.join();
+    }
+}
+
+void SoapyWorker::start(SoapySDR::Device *device)
+{
+    m_device = device;
+    underflows = 0;
+    overflows = 0;
+    running = true;
+    m_thread = std::thread(&SoapyWorker::process_start, this);
+}
+
+void SoapyWorker::process_start()
+{
+    // Set thread priority to realtime
+    if (int ret = set_realtime_prio(1)) {
+        etiLog.level(error) << "Could not set priority for SoapySDR worker:" << ret;
+    }
+
+    set_thread_name("soapyworker");
+
+    std::vector<size_t> channels;
+    channels.push_back(0);
+    auto stream = m_device->setupStream(SOAPY_SDR_TX, "CF32", channels);
+    m_device->activateStream(stream);
+    process(stream);
+    m_device->closeStream(stream);
+    running = false;
+    etiLog.level(warn) << "SoapySDR worker terminated";
+}
+
+void SoapyWorker::process(SoapySDR::Stream *stream)
+{
+    while (running) {
+        struct SoapyWorkerFrameData frame;
+        queue.wait_and_pop(frame);
+
+        // The frame buffer contains bytes representing FC32 samples
+        const complexf *buf = reinterpret_cast<complexf*>(frame.buf.data());
+        const size_t numSamples = frame.buf.size() / sizeof(complexf);
+        if ((frame.buf.size() % sizeof(complexf)) != 0) {
+            throw std::runtime_error("OutputSoapy: invalid buffer size");
+        }
+
+        // Stream MTU is in samples, not bytes.
+        const size_t mtu = m_device->getStreamMTU(stream);
+
+        size_t num_acc_samps = 0;
+        while (running && (num_acc_samps < numSamples)) {
+            const void *buffs[1];
+            buffs[0] = buf + num_acc_samps;
+
+            const size_t samps_to_send = std::min(numSamples - num_acc_samps, mtu);
+
+            int flags = 0;
+
+            auto ret = m_device->writeStream(stream, buffs, samps_to_send, flags);
+
+            if (ret == SOAPY_SDR_TIMEOUT) {
+                continue;
+            }
+            else if (ret == SOAPY_SDR_OVERFLOW) {
+                overflows++;
+                continue;
+            }
+            else if (ret == SOAPY_SDR_UNDERFLOW) {
+                underflows++;
+                continue;
+            }
+
+            if (ret < 0) {
+                etiLog.level(error) << "Unexpected stream error " <<
+                    SoapySDR::errToStr(ret);
+                running = false;
+            }
+
+            num_acc_samps += ret;
+        }
+    }
+}
+
+int OutputSoapy::process(Buffer* dataIn)
+{
+    if (first_run) {
+        m_worker.start(m_device);
+        first_run = false;
+    }
+    else if (!m_worker.running) {
+        etiLog.level(error) << "OutputSoapy: worker thread died";
+        throw std::runtime_error("Fault in OutputSoapy");
+    }
+
+    SoapyWorkerFrameData frame;
+    m_eti_source->calculateTimestamp(frame.ts);
+
+
+    if (frame.ts.fct == -1) {
+        etiLog.level(info) <<
+            "OutputSoapy: dropping one frame with invalid FCT";
+    }
+    else {
+        const uint8_t* pInData = reinterpret_cast<uint8_t*>(dataIn->getData());
+        frame.buf.resize(dataIn->getLength());
+        std::copy(pInData, pInData + dataIn->getLength(),
+                frame.buf.begin());
+        m_worker.queue.push_wait_if_full(frame, FRAMES_MAX_SIZE);
+    }
+
+    return dataIn->getLength();
+}
+
+
+void OutputSoapy::setETISource(EtiSource *etiSource)
+{
+    m_eti_source = etiSource;
+}
+
+void OutputSoapy::set_parameter(const string& parameter, const string& value)
+{
+    stringstream ss(value);
+    ss.exceptions ( stringstream::failbit | stringstream::badbit );
+
+    if (parameter == "txgain") {
+        ss >> m_conf.txgain;
+        m_device->setGain(SOAPY_SDR_TX, 0, m_conf.txgain);
+    }
+    else if (parameter == "freq") {
+        ss >> m_conf.frequency;
+        m_device->setFrequency(SOAPY_SDR_TX, 0, m_conf.frequency);
+    m_conf.frequency = m_device->getFrequency(SOAPY_SDR_TX, 0);
+    }
+    else if (parameter == "underflows") {
+        throw ParameterError("Parameter 'underflows' is read-only");
+    }
+    else if (parameter == "overflows") {
+        throw ParameterError("Parameter 'overflows' is read-only");
+    }
+    else {
+        stringstream ss;
+        ss << "Parameter '" << parameter
+            << "' is not exported by controllable " << get_rc_name();
+        throw ParameterError(ss.str());
+    }
+}
+
+const string OutputSoapy::get_parameter(const string& parameter) const
+{
+    stringstream ss;
+    if (parameter == "txgain") {
+        ss << m_conf.txgain;
+    }
+    else if (parameter == "freq") {
+        ss << m_conf.frequency;
+    }
+    else if (parameter == "underflows") {
+        ss << m_worker.underflows;
+    }
+    else if (parameter == "overflows") {
+        ss << m_worker.overflows;
+    }
+    else {
+        ss << "Parameter '" << parameter <<
+            "' is not exported by controllable " << get_rc_name();
+        throw ParameterError(ss.str());
+    }
+    return ss.str();
+}
+
+#endif // HAVE_SOAPYSDR
+
diff --git a/src/OutputSoapy.h b/src/OutputSoapy.h
new file mode 100644
index 0000000..230f11b
--- /dev/null
+++ b/src/OutputSoapy.h
@@ -0,0 +1,138 @@
+/*
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Her Majesty the
+   Queen in Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2017
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://opendigitalradio.org
+
+DESCRIPTION:
+   It is an output driver using the SoapySDR library that can output to
+   many devices.
+*/
+
+/*
+   This file is part of ODR-DabMod.
+
+   ODR-DabMod is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of the
+   License, or (at your option) any later version.
+
+   ODR-DabMod is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with ODR-DabMod.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#ifdef HAVE_CONFIG_H
+#   include <config.h>
+#endif
+
+#ifdef HAVE_SOAPYSDR
+#include <SoapySDR/Version.hpp>
+#include <SoapySDR/Modules.hpp>
+#include <SoapySDR/Registry.hpp>
+#include <SoapySDR/Device.hpp>
+
+#include <string>
+#include <memory>
+
+#include "ModPlugin.h"
+#include "EtiReader.h"
+#include "RemoteControl.h"
+#include "ThreadsafeQueue.h"
+
+typedef std::complex<float> complexf;
+
+/* This structure is used as initial configuration for the Soapy output.
+ * It must also contain all remote-controllable settings, otherwise
+ * they will get lost on a modulator restart. */
+struct OutputSoapyConfig {
+    std::string device;
+
+    long masterClockRate = 32768000;
+    unsigned sampleRate = 2048000;
+    double frequency = 0.0;
+    double txgain = 0.0;
+    unsigned dabMode = 0;
+};
+
+// Each frame contains one OFDM frame, and its
+// associated timestamp
+struct SoapyWorkerFrameData {
+    // Buffer holding frame data
+    std::vector<uint8_t> buf;
+
+    // A full timestamp contains a TIST according to standard
+    // and time information within MNSC with tx_second.
+    struct frame_timestamp ts;
+};
+
+class SoapyWorker
+{
+    public:
+        ThreadsafeQueue<SoapyWorkerFrameData> queue;
+        SoapySDR::Device *m_device;
+        std::atomic<bool> running;
+        size_t underflows;
+        size_t overflows;
+
+        SoapyWorker() {}
+        SoapyWorker(const SoapyWorker&) = delete;
+        SoapyWorker operator=(const SoapyWorker&) = delete;
+        ~SoapyWorker() { stop(); }
+
+        void start(SoapySDR::Device *device);
+        void stop(void);
+
+    private:
+        std::thread m_thread;
+
+        void process_start(void);
+        void process(SoapySDR::Stream *stream);
+};
+
+class OutputSoapy: public ModOutput, public RemoteControllable
+{
+    public:
+        OutputSoapy(OutputSoapyConfig& config);
+        OutputSoapy(const OutputSoapy& other) = delete;
+        OutputSoapy& operator=(const OutputSoapy& other) = delete;
+        ~OutputSoapy();
+
+        int process(Buffer* dataIn);
+
+        const char* name() { return "OutputSoapy"; }
+
+        void setETISource(EtiSource *etiSource);
+
+        /*********** REMOTE CONTROL ***************/
+
+        /* Base function to set parameters. */
+        virtual void set_parameter(const std::string& parameter,
+                const std::string& value);
+
+        /* Getting a parameter always returns a string. */
+        virtual const std::string get_parameter(
+                const std::string& parameter) const;
+
+
+    protected:
+        SoapyWorker m_worker;
+        EtiSource *m_eti_source;
+        OutputSoapyConfig& m_conf;
+
+        SoapySDR::Device *m_device;
+
+        bool first_run = true;
+};
+
+
+#endif //HAVE_SOAPYSDR
diff --git a/src/OutputUHD.cpp b/src/OutputUHD.cpp
index d26ce77..b4344f5 100644
--- a/src/OutputUHD.cpp
+++ b/src/OutputUHD.cpp
@@ -49,6 +49,9 @@
 
 using namespace std;
 
+// Maximum number of frames that can wait in uwd.frames
+static const size_t FRAMES_MAX_SIZE = 2;
+
 typedef std::complex<float> complexf;
 
 std::string stringtrim(const std::string &s)
diff --git a/src/OutputUHD.h b/src/OutputUHD.h
index 9766f36..e477e47 100644
--- a/src/OutputUHD.h
+++ b/src/OutputUHD.h
@@ -71,9 +71,6 @@ DESCRIPTION:
 // frames are too far in the future
 #define TIMESTAMP_MARGIN_FUTURE 0.5
 
-// Maximum number of frames that can wait in uwd.frames
-#define FRAMES_MAX_SIZE 2
-
 typedef std::complex<float> complexf;
 
 // Each frame contains one OFDM frame, and its
diff --git a/src/Utils.cpp b/src/Utils.cpp
index b93f2c1..f4610a4 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -131,3 +131,50 @@ void set_thread_name(const char *name)
     prctl(PR_SET_NAME,name,0,0,0);
 }
 
+double parseChannel(const std::string& chan)
+{
+    double freq;
+    if      (chan == "5A") freq = 174928000;
+    else if (chan == "5B") freq = 176640000;
+    else if (chan == "5C") freq = 178352000;
+    else if (chan == "5D") freq = 180064000;
+    else if (chan == "6A") freq = 181936000;
+    else if (chan == "6B") freq = 183648000;
+    else if (chan == "6C") freq = 185360000;
+    else if (chan == "6D") freq = 187072000;
+    else if (chan == "7A") freq = 188928000;
+    else if (chan == "7B") freq = 190640000;
+    else if (chan == "7C") freq = 192352000;
+    else if (chan == "7D") freq = 194064000;
+    else if (chan == "8A") freq = 195936000;
+    else if (chan == "8B") freq = 197648000;
+    else if (chan == "8C") freq = 199360000;
+    else if (chan == "8D") freq = 201072000;
+    else if (chan == "9A") freq = 202928000;
+    else if (chan == "9B") freq = 204640000;
+    else if (chan == "9C") freq = 206352000;
+    else if (chan == "9D") freq = 208064000;
+    else if (chan == "10A") freq = 209936000;
+    else if (chan == "10B") freq = 211648000;
+    else if (chan == "10C") freq = 213360000;
+    else if (chan == "10D") freq = 215072000;
+    else if (chan == "11A") freq = 216928000;
+    else if (chan == "11B") freq = 218640000;
+    else if (chan == "11C") freq = 220352000;
+    else if (chan == "11D") freq = 222064000;
+    else if (chan == "12A") freq = 223936000;
+    else if (chan == "12B") freq = 225648000;
+    else if (chan == "12C") freq = 227360000;
+    else if (chan == "12D") freq = 229072000;
+    else if (chan == "13A") freq = 230784000;
+    else if (chan == "13B") freq = 232496000;
+    else if (chan == "13C") freq = 234208000;
+    else if (chan == "13D") freq = 235776000;
+    else if (chan == "13E") freq = 237488000;
+    else if (chan == "13F") freq = 239200000;
+    else {
+        std::cerr << "       soapy output: channel " << chan << " does not exist in table\n";
+        throw std::out_of_range("soapy channel selection error");
+    }
+    return freq;
+}
diff --git a/src/Utils.h b/src/Utils.h
index 46c46d5..e2b8a2f 100644
--- a/src/Utils.h
+++ b/src/Utils.h
@@ -3,7 +3,7 @@
    Her Majesty the Queen in Right of Canada (Communications Research
    Center Canada)
 
-   Copyright (C) 2015
+   Copyright (C) 2017
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://opendigitalradio.org
@@ -25,8 +25,7 @@
    along with ODR-DabMod.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef __UTILS_H_
-#define __UTILS_H_
+#pragma once
 
 #ifdef HAVE_CONFIG_H
 #   include "config.h"
@@ -36,6 +35,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <time.h>
+#include <string>
 
 void printUsage(char* progName);
 
@@ -62,5 +62,6 @@ int set_realtime_prio(int prio);
 
 void set_thread_name(const char *name);
 
-#endif
+// Convert a channel like 10A to a frequency
+double parseChannel(const std::string& chan);