Added direct sampling

doc/rtl_power_fftw.1.md

@@ -65,6 +65,9 @@ The program can be stopped gracefully by sending the SIGINT signal to it (pressi
 `-r <Hz>`,  `--rate <Hz>`
 :   Sample rate of the receiver in Hz.
 
+`-D <int>`,  `--diret-sampling <0,1,2>`
+:   Set direct sampling (0=NO,1=I,2=Q).
+
 `-s <bytes>`,  `--buffer-size <bytes>`
 :   Size of the read buffers (leave it as it is unless you know what you are doing).
 

src/device.cxx

@@ -69,6 +69,16 @@ std::vector<int> Rtlsdr::gains() const {
   return gains;
 }
 
+uint32_t Rtlsdr::direct_sampling() const {
+  uint32_t direct_sampling = rtlsdr_get_direct_sampling(dev);
+  if (direct_sampling != 0 && direct_sampling != 1 && direct_sampling != 2) {
+    throw RPFexception(
+      "RTL device: could not read direct sampling.",
+      ReturnValue::HardwareError);
+  }
+  return direct_sampling;
+}
+
 uint32_t Rtlsdr::sample_rate() const {
   uint32_t sample_rate = rtlsdr_get_sample_rate(dev);
   if (sample_rate == 0) {
@@ -108,6 +118,14 @@ void Rtlsdr::set_gain(int gain) {
   }
 }
 
+void Rtlsdr::set_direct_sampling(int direct_sampling) {
+  if (rtlsdr_set_direct_sampling(dev, direct_sampling)) {
+    throw RPFexception(
+      "RTL device: could not set direct sampling.",
+      ReturnValue::HardwareError);
+  }
+}
+
 void Rtlsdr::set_frequency(uint32_t frequency) {
   if (rtlsdr_set_center_freq(dev, frequency) < 0) {
     throw RPFexception(

src/device.h

@@ -35,12 +35,14 @@ class Rtlsdr {
 
   // Reading parameters & data.
   std::vector<int> gains() const;
+  uint32_t direct_sampling() const;
   uint32_t sample_rate() const;
   uint32_t frequency() const ;
   bool read(Buffer& buffer) const;
 
   // Parameter setting.
   void set_gain(int gain);
+  void set_direct_sampling(int direct_sampling);
   void set_frequency(uint32_t frequency);
   void set_freq_correction(int ppm_error);
   void set_sample_rate(uint32_t sample_rate);

src/params.cxx

@@ -113,6 +113,8 @@ Params::Params(int argc, char** argv) {
     cmd.add( arg_bufferlen );
     TCLAP::ValueArg<int> arg_rate("r","rate","Sample rate of the receiver.",false,sample_rate,"samples/s");
     cmd.add( arg_rate );
+    TCLAP::ValueArg<int> arg_direct_sampling("D","direct-sampling","Direct sampling of the receiver.",false,direct_sampling,"0=NO,1=I,2=Q");
+    cmd.add( arg_direct_sampling );
     TCLAP::SwitchArg arg_quiet("q","quiet","Limit verbosity.", talkless);
     cmd.add( arg_quiet );
     TCLAP::ValueArg<int> arg_ppm("p","ppm","Set custom ppm error in RTL-SDR device.", false, ppm_error, "ppm");
@@ -156,6 +158,7 @@ Params::Params(int argc, char** argv) {
     linear = arg_linear.getValue();
     gain = arg_gain.getValue();
     sample_rate = arg_rate.getValue();
+    direct_sampling = arg_direct_sampling.getValue();
     buffers = arg_buffers.getValue();
     buf_length = arg_bufferlen.getValue();
     endless = arg_continue.getValue();

src/params.h

@@ -60,6 +60,7 @@ class Params {
   bool talkless = false;  // default: verbose
   bool matrixMode = false;  // default: original rtl-power-fftw output format
   int finalfreq = 0;
+  int direct_sampling = 0;
   std::string matrix_file;  // just name without extension
   std::string bin_file; // name with .bin extension
   std::string freq_file; // name with .frq extension

src/rtl_power_fftw.cxx

@@ -81,6 +81,11 @@ int main(int argc, char **argv)
               << " (" << 0.1*gain << " dB)" << std::endl;
     rtldev.set_gain(gain);
 
+    // Set direct sampling
+    rtldev.set_direct_sampling(params.direct_sampling);
+    int direct_sampling = rtldev.direct_sampling();
+    std::cerr << "Actual direct sampling: " << direct_sampling << std::endl;
+
     // Temporarily set the frequency to params.cfreq, just so that the device does not
     // complain upon setting the sample rate. If this fails, it's not a big deal:
     // the sample rate will be read out just fine, but librtlsdr _might_ print an