Utility to send I/Q samples read from a SDR device over the network via UDP
Python C++ CMake C QMake

README.md

SDRdaemon

SDRdaemon can be used to send I/Q samples read from a SDR device over the network via UDP.

Introduction

SDRdaemon is a basic software-defined radio receiver that just sends the I/Q samples over the network via UDP. It was developed on the base of NGSoftFM (also found in this Github repo: https://github.com/f4exb/ngsoftfm) and shares a lot of the code for the interface with the SDR hardware devices.

It conveys meta data in the data flow so that the receiving application is informed about parameters essential to render correctly the data coming next such as the sample rate, the number of bytes used for the samples, the number of effective sample bits, the center frequency... (See the "Data format" chapter for detals).

While running the program accepts configuration commands on a TCP port using nanomsg messages with a content in the same format as the configuration string given on the command line (See the "Running" chapter for details). This provides a dynamic control of the device or features of the application such as the decimation. A Python script is provided to send such messages.

Hardware supported:

  • RTL-SDR based (RTL2832-based) hardware is supported and uses the librtlsdr library to interface with the RTL-SDR hardware.
  • HackRF One and variants are supported with libhackrf library.
  • Airspy is supported with libairspy library.
  • BladeRF is supported with libbladerf library.

SDRdaemon can be used conveniently along with SDRangel (found in this Github repo: https://github.com/f4exb/sdrangel) as the client application. So in this remote type of configuration you will need both an angel and a daemon :-)

GNUradio is also supported with a specific source block provided in the gr-sdrdaemon subdirectory.

SDRdaemon requires:

For the latest version, see https://github.com/f4exb/SDRdaemon

Branches:

  • master is the "production" branch with the most stable release
  • dev is the development branch that contains current developments that will be eventually released in the master branch
  • fix contains fixes that cannot wait for the dev branch to go to production

Prerequisites

Base requirements

  • sudo apt-get install cmake pkg-config libusb-1.0-0-dev libasound2-dev libboost-all-dev liblz4-dev libnanomsg-dev

Forward Erasure Correction (FEC) support

To enable the version with FEC (sdrdaemonfec binary and libsdrdmnfec) you have to install CM256cc. You will then have to specify the include and library paths on the cmake command line. Say if you install cm256cc in /opt/install/cm256cc you will have to add -DCM256CC_INCLUDE_DIR=/opt/install/cm256cc/include/cm256cc -DCM256CC_LIBRARIES=/opt/install/cm256cc/lib/libcm256cc.so to the cmake commands.

The GNUradio source block supporting FEC is located in the gr-sdrdaemonfec subdirectory.

The binary sdrdaemonfec has the same features than sdrdaemon but in addition it supports FEC using the -f option. It also recognizes the configuration commmand fecblk to specify the number of FEC blocks. When enabling FEC with the -f option the frame structure is quite different than when FEC is not enabled. The structure is described in the Data Format section. Even when fecblk=0 is specified in the commands and hence no FEC blocks are enabled the data structure is the same.

In FEC enabled format frames and blocks are numbered and even if no FEC blocks are added this can help in reconstructing frames with appropriate timings.

Airspy support

Airspy support must be installed for SDRdaemon to work with an Airspy device.

If you install from source (https://github.com/airspy/host/tree/master/libairspy) in your own installation path you have to specify the include path and library path. For example if you installed it in /opt/install/libairspy you have to add -DLIBAIRSPY_LIBRARIES=/opt/install/libairspy/lib/libairspy.so -DLIBAIRSPY_INCLUDE_DIR=/opt/install/libairspy/include to the cmake options.

To install the library from a Debian/Ubuntu installation just do:

  • sudo apt-get install libairspy-dev

BladeRF support

BladeRF support must be installed for SDRdaemon to work with a BladeRF device.

If you install from source (https://github.com/Nuand/bladeRF) in your own installation path you have to specify the include path and library path. For example if you installed it in /opt/install/libbladerf you have to add -DLIBBLADERF_LIBRARIES=/opt/install/libbladeRF/lib/libbladeRF.so -DLIBBLADERF_INCLUDE_DIR=/opt/install/libbladeRF/include to the cmake options.

To install the library from a Debian/Ubuntu installation just do:

  • sudo apt-get install libbladerf-dev

Note: for the BladeRF to work effectively on FM broadcast frequencies you have to fit it with the XB200 extension board.

HackRF support

HackRF support must be installed for SDRdaemon to work with a HackRF device.

If you install from source (https://github.com/mossmann/hackrf/tree/master/host/libhackrf) in your own installation path you have to specify the include path and library path. For example if you installed it in /opt/install/libhackrf you have to add -DLIBHACKRF_LIBRARIES=/opt/install/libhackrf/lib/libhackrf.so -DLIBHACKRF_INCLUDE_DIR=/opt/install/libhackrf/include to the cmake options.

To install the library from a Debian/Ubuntu installation just do:

  • sudo apt-get install libhackrf-dev

RTL-SDR support

The Osmocom RTL-SDR library must be installed before you can use SDRdaemon with a RTL-SDR device. See http://sdr.osmocom.org/trac/wiki/rtl-sdr for more information. SDRdaemon has been tested successfully with RTL-SDR 0.5.3. Normally your distribution should provide the appropriate librtlsdr package. If you go with your own installation of librtlsdr you have to specify the include path and library path. For example if you installed it in -DLIBRTLSDR_LIBRARIES=/opt/install/librtlsdr/lib/librtlsdr.so -DLIBRTLSDR_INCLUDE_DIR=/opt/install/librtlsdr/include to the cmake options

To install the library from a Debian/Ubuntu installation just do:

  • sudo apt-get install librtlsdr-dev

nanomsg custom installation

If you build nanomsg from source obtained either by git clone or a released source package and install it in your own path (ex: /opt/install/nanomsg) you will need to specify the include and library paths like this: -DLIBNANOMSG_LIBRARIES=/opt/install/nanomsg/lib/libnanomsg.so -DLIBNANOMSG_INCLUDE_DIR=/opt/install/nanomsg/include

Installing

To install SDRdaemon, download and unpack the source code and go to the top level directory. Then do like this:

  • mkdir build
  • cd build
  • cmake ..

Compile and install

  • make -j8 (for machines with 8 CPUs)
  • make install

Running

Examples

Typical commands:

  • RTL-SDR: ./sdrdaemon -t rtlsdr -I 192.168.1.3 -D 9090 -C 9091 -c txdelay=300,freq=433970000,srate=1000000,ppmp=58,gain=40.2,decim=5,fcpos=2
    • Use RTL-SDR device #0
    • Destination address for the data is: 192.168.1.3
    • Using UDP port 9090 for the data (it is the default anyway)
    • Using TCP port 9091 to listen to configuration commands (it is the default anyway)
    • Startup configuration:
      • Center frequency: 433.97 MHz
      • Device sample rate: 1 MHz
      • Local oscillator correction: 58 ppm
      • RF gain: 40.2 dB
      • Decimation: 2^5 = 32; thus stream sample rate is 31.25 kHz
      • Position of center frequency: 2 is centered (decimation around the center)
  • RTL-SDR with FEC enabled: ./sdrdaemonfec -f -t rtlsdr -I 192.168.1.3 -D 9090 -C 9091 -c txdelay=300,fecblk=8,freq=433970000,srate=1000000,ppmp=58,gain=40.2,decim=5,fcpos=2. Additional commands from the previous command:
    • -f option to enable FEC
    • fecblk=8: add 8 FEC blocks to the 128 blocks data frame resulting in a total of 136 blocks per frame.
  • Airspy: ./sdrdaemon -t airspy -I 192.168.1.3 -D 9090 -c txdelay=300,freq=433970000,srate=10000000,ppmn=1.7,lgain=13,mgain=9,vgain=6,decim=5,fcpos=0
    • Use Airspy device #0
    • Destination address for the data is: 192.168.1.3
    • Using UDP port 9090 for the data (it is the default anyway)
    • Using TCP port 9091 to listen to configuration commands (it is the default anyway)
    • Startup configuration:
      • Center frequency: 433.97 MHz
      • Device sample rate: 10 MHz
      • LO correction: -1.7 ppm
      • LNA gain: 13 dB
      • Mixer gain: 9 dB
      • VGA gain: 6 dB
      • Decimation: 2^5 = 32; thus stream sample rate is 312.5 kHz
      • Position of center frequency: 0 is infra-dyne (decimation around -fc/4)
  • HackRF: ./sdrdaemon -t hackrf -I 192.168.1.3 -D 9090 -c txdelay=300,freq=433970000,srate=3200000,lgain=32,vgain=24,bwfilter=1.75,decim=3,fcpos=1
    • Use HackRF device #0
    • Destination address for the data is: 192.168.1.3
    • Using UDP port 9090 for the data (it is the default anyway)
    • Using TCP port 9091 to listen to configuration commands (it is the default anyway)
    • Startup configuration:
      • Center frequency: 433.97 MHz
      • Device sample rate: 3.2 MHz
      • LNA gain: 32 dB
      • VGA gain: 24 dB
      • Decimation: 2^3 = 8; thus stream sample rate is 400 kHz
      • Position of center frequency: 1 is supra-dyne (decimation around fc/4)
  • BladeRF: ./sdrdaemon -t bladerf -I 192.168.1.3 -D 9090 -c txdelay=300,freq=433900000,srate=3200000,lgain=6,v1gain=6,v2gain=3,decim=3,bw=2500000,fcpos=1
    • Use BladeRF device #0
    • Destination address for the data is: 192.168.1.3
    • Using UDP port 9090 for the data (it is the default anyway)
    • Using TCP port 9091 to listen to configuration commands (it is the default anyway)
    • Startup configuration:
      • Center frequency: 433.9 MHz
      • Device sample rate: 3.2 MHz
      • RF filter bandwidth: 2.5 MHz
      • LNA gain: 6 dB
      • VGA1 gain: 6 dB
      • VGA2 gain: 3 dB
      • Decimation: 2^3 = 8; thus stream sample rate is 400 kHz
      • Position of center frequency: 1 is supra-dyne (decimation around fc/4)
  • Test signal source: ./sdrdaemon -t test -I 192.168.1.3 -D 9090 -c power=40,decim=2,srate=500000,dfp=25000
    • Destination address for the data is: 192.168.1.3
    • Using UDP port 9090 for the data (it is the default anyway)
    • Carrier relative power is -40 dB
    • Base sample rate is 500 kHz
    • Decimation is 2^2 = 4; thus stream sample rate is 125 kHz
    • Carrier frequency shift from the center is 25 kHz

All options

  • -t devtype is mandatory and must be either (depending on support libraries installed):
    • rtlsdr for RTL-SDR devices
    • hackrf for HackRF devices
    • airspy for Airspy
    • bladerf for BladeRF
    • test for test signal source (always available)
  • -c config Comma separated list of configuration options as key=value pairs or just key for switches. Depends on device type (see next paragraphs).
  • -d devidx Device index, 'list' to show device list (default 0)
  • -f Activate FEC (sdrdaemonfec only)
  • -r pcmrate Audio sample rate in Hz (default 48000 Hz)
  • -M Disable stereo decoding
  • -R filename Write audio data as raw S16_LE samples. Use filename - to write to stdout
  • -W filename Write audio data to .WAV file
  • -P [device] Play audio via ALSA device (default default). Use aplay -L to get the list of devices for your system
  • -T filename Write pulse-per-second timestamps. Use filename '-' to write to stdout
  • -z bytes Compress I/Q data using LZ4 algorithm with a minimum number of bytes for each frame. It will default to at least 64kB.

Common configuration option for UDP transmission

  • txdelay=<int> delay between the transmission of successive UDP blocks in microseconds. This may not result in the exact delay in microseconds as this is in fact the argument to usleep function. The system guarantees that at least this delay is respected and in many practical cases it is not possible to have a delay smaller than ~100 microseconds. You may adjust this number depending on the speed of your link. This prevents UDP congestion by mitigating competition between the process sending blocks as fast as possible and the IP link absorbing them.

Common configuration option for Forward Erasure Correction when enabled

  • fecblk=<int> value should be between 0 (no FEC) and 127. This is the number of FEC blocks added to the 128 I/Q data blocks sent per frame. See the "Data formats" chapter for details about the frame construction in the FEC case.

Common configuration options for the decimation

  • decim=<int> log2 of the decimation factor. Samples collected from the device are down-sampled by two to the power of this value. On 8 bit samples native systems (RTL-SDR and HackRF) For a value greater than 0 (thus an effective downsampling) the size of the samples is increased to 2x16 bits.
  • fcpos=<int> Relative position of the center frequency in the resulting decimation:
    • 0 is infra-dyne i.e. decimation is done around -fc/4 where fc is the device center frequency
    • 1 is supra-dyne i.e. decimation is done around fc/4
    • 2 is centered i.e. decimation is done around fc

Device type specific configuration options

Note that these options can be used both as the initial configuration as the argument of the -c option and as the dynamic configuration sent on the UDP configuration port specified by the -C option.

RTL-SDR

  • freq=<int> Desired tune frequency in Hz. Accepted range from 10M to 2.2G. (default 100M: 100000000)
  • gain=<x> (default auto)
    • auto Selects gain automatically
    • list Lists available gains and exit
    • <float> gain in dB. Possible gains in dB are: 0.0, 0.9, 1.4, 2.7, 3.7, 7.7, 8.7, 12.5, 14.4, 15.7, 16.6, 19.7, 20.7, 22.9, 25.4, 28.0, 29.7, 32.8, 33.8, 36.4, 37.2, 38.6, 40.2, 42.1, 43.4, 43.9, 44.5, 48.0, 49.6
  • srate=<int> Device sample rate. valid values in the [225001, 300000], [900001, 3200000] ranges. (default 1000000)
  • ppmp=<int> Argument is positive. Positive LO correction in ppm. LO is corrected by this value in ppm
  • ppmn=<int> Argument is positive. Negative LO correction in ppm. LO is corrected by minus this value in ppm. If ppmp is also specified ppmp takes precedence.
  • blklen=<int> Device read buffer length in number of samples (default 64kS)
  • agc Activates device AGC (default off)

HackRF

  • freq=<float> Desired tune frequency in Hz. Valid range from 1M to 6G. (default 100M: 100000000)
  • srate=<float> Device sample rate (default 5000000). Valid values from 1M to 20M. In fact rates lower than 10M are not specified in the datasheets of the ADC chip however a rate of 1000000 (1M) still works well with SDRdaemon.
  • ppmp=<float> Argument is positive. Positive LO correction in ppm. LO is corrected by this value in ppm
  • ppmn=<float> Argument is positive. Negative LO correction in ppm. LO is corrected by minus this value in ppm. If ppmp is also specified ppmp takes precedence.
  • lgain=<x> LNA gain in dB. Valid values are: 0, 8, 16, 24, 32, 40, list. list lists valid values and exits. (default 16)
  • vgain=<x> VGA gain in dB. Valid values are: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, list. list lists valid values and exits. (default 22)
  • bwfilter=<x> RF (IF) filter bandwidth in MHz. Actual value is taken as the closest to the following values: 1.75, 2.5, 3.5, 5, 5.5, 6, 7, 8, 9, 10, 12, 14, 15, 20, 24, 28, list. list lists valid values and exits. (default 2.5)
  • extamp Turn on the extra amplifier (default off)
  • antbias Turn on the antenna bias for remote LNA (default off)

Airspy

  • freq=<int> Desired tune frequency in Hz. Valid range from 1M to 1.8G. (default 100M: 100000000)
  • srate=<int> Device sample rate. list lists valid values and exits. (default 10000000). Valid values depend on the Airspy firmware. Airspy firmware and library must support dynamic sample rate query.
  • ppmp=<float> Argument is positive. Positive LO correction in ppm. LO is corrected by this value in ppm
  • ppmn=<float> Argument is positive. Negative LO correction in ppm. LO is corrected by minus this value in ppm. If ppmp is also specified ppmp takes precedence.
  • lgain=<x> LNA gain in dB. Valid values are: 0, 1, 2, 3, 4, 5, 6, 7, 8 ,9 ,10, 11 12, 13, 14, list. list lists valid values and exits. (default 8)
  • mgain=<x> Mixer gain in dB. Valid values are: 0, 1, 2, 3, 4, 5, 6, 7, 8 ,9 ,10, 11 12, 13, 14, 15, list. list lists valid values and exits. (default 8)
  • vgain=<x> VGA gain in dB. Valid values are: 0, 1, 2, 3, 4, 5, 6, 7, 8 ,9 ,10, 11 12, 13, 14, 15, list. list lists valid values and exits. (default 0)
  • antbias Turn on the antenna bias for remote LNA (default off)
  • lagc Turn on the LNA AGC (default off)
  • magc Turn on the mixer AGC (default off)

BladeRF

  • freq=<int> Desired tune frequency in Hz. Valid range low boundary depends whether the XB200 extension board is fitted (default 300000000).
    • XB200 fitted: 100kHz to 3,8 GHz
    • XB200 not fitted: 300 MHZ to 3.8 GHz.
  • srate=<int> Device sample rate in Hz. Valid range is 48kHZ to 40MHz. (default 1000000).
  • bw=<int> IF filter bandwidth in Hz. list lists valid values and exits. (default 1500000).
  • lgain=<x> LNA gain in dB. Valid values are: 0, 3, 6, list. list lists valid values and exits. (default 3)
  • v1gain=<x> VGA1 gain in dB. Valid values are: 5, 6, 7, 8 ,9 ,10, 11 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, list. list lists valid values and exits. (default 20)
  • v2gain=<x> VGA2 gain in dB. Valid values are: 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, list. list lists valid values and exits. (default 9)

Test

  • freq=<int> Desired center frequency in Hz sent in the meta data. Valid range 10 kHz to 10 GHz exclusive (default 435000000 i.e. 435 MHz).
  • srate=<int> Base sample rate in Hz. Valid range is 8kHZ to 10MHz. (default 5000000 i.e. 5 MS/s).
  • power=<int> Relative power of CW signaler in negative dB (i.e. 40 is -40 dB) (default 0).
  • dfp=<int> Positive shift frequency of carrier from center frequency in Hz (default 100000 i.e. 100 kHz)
  • dfn=<int> Negative shift frequency of carrier from center frequency in Hz (default 100000 i.e. -100 kHz)
  • blklen=<int> Waveform buffer length in number of samples (default 64kS)

Dynamic remote control

SDRdaemon listens on a TCP port (the configuration port) for incoming nanomsg messages consisting of a configuration string as described just above. You can use the utility sdrdmnctl in the bin directory of the installation directory (sits along sdrdaemon) to send such messages. It defaults to the localhost (127.0.0.1) and port 9091. The configuration string is given as the -c option (same as for sdrdaemon). Example:

/opt/install/sdrdaemon/bin/sdrdmnctl -I 192.168.1.3 -C 9999 -c frequency=433970000

The complete list of options is:

  • -I IP address (or name defined by the DNS) of the machine hosting SDRdaemon (default 127.0.0.1).
  • -C TCP port where SDRdaemon listens for configuration commands using nanomsg (default: 9091).
  • -c message string. This is where you specify the configuration as a comma separated list of key=values (default: freq=100000000).
  • -t timeout in seconds. Timeout after which communication with SDRdaemon is abandoned (default: 2).
  • -h online help

The nanomsg connection is specified as a paired connection (NN_PAIR). The connection can be managed by any program at the convenience of the user as long as the connection type is respected.

Data formats

With FEC

Packaging

The I/Q data is sent in frames of 128 fixed size data blocks including a first block ("block zero") containing only meta data and a variable number of FEC blocks up to 127 FEC blocks. It is possible to use this scheme without FEC in which case no additional FEC blocks are present. All blocks have a fixed size of 512 bytes that represent the UDP payload size. The first 4 bytes are occupied by signalling data consisting of a 2 bytes frame count (wraps around at 65535), a 1 byte block count (0 to 127 (min) or 255 (max)) and a 1 byte filler. The rest is occupied by either the meta data (block zero), actual I/Q samples (127 samples per block resulting in 508 bytes) for data bytes or FEC data. The FEC is calculated on the 128 blocks of 508 bytes of meta data and I/Q samples.

Meta data block

The block of "meta" data consists of the following (values expressed in bytes):

Offset Length Type Content
0 4 unsigned integer Center frequency of reception in kHz
4 4 unsigned integer Stream sample rate (Samples/second)
8 1 unsigned char number of bytes per sample. Practically 1 or 2
9 1 unsigned char number of effective bits per sample. Practically 8 to 16
10 1 unsigned char number of (FEC protected) data blocks. Practically 128
11 1 unsigned char number of FEC blocks. Practically 0 to 127
12 4 unsigned integer Seconds of Unix timestamp at the beginning of the sending processing
16 4 unsigned integer Microseconds of Unix timestamp at the beginning of the sending processing
20 4 unsigned integer CRC32 of the above (20 bytes)

Total size is 24 bytes. The 484 (!) remaining bytes are reserved for future use.

Without FEC

Packaging

The block of data retrieved from the hardware device is sliced into blocks of the UDP payload size. This sequence of blocks is called a "frame" in the following. A special block called the "meta" block is sent before a frame. It is used to convey "meta" data about the frame and its data that follows. A CRC on 64 bits is calculated on this "meta" data and appended to it. It serves as a verification and also to recognize the "meta" block from the data blocks thus achieving synchronization. There is effectively a very low probability to mix it up with a data block.

A compressed stream may pack several data blocks retrieved from the hardware in one frame to improve compression efficiency. So the case may arise that a change of meta data occurs from one "hardware" block to the next in the same frame. In this case the frame is split and a new frame is constructed with a starting "meta" block from the block where the meta data has changed. The first part of the original frame being sent immediately over UDP. This ensures that the data frame and its "meta" block are always consistent.

Meta data block

The block of "meta" data consists of the following (values expressed in bytes):

Offset Length Type Content
0 8 unsigned integer Center frequency of reception in Hz
8 4 unsigned integer Stream sample rate (Samples/second)
12 1([7:5]) bitfield Reserved
12 1([4]) bitfield Stream is compressed with LZ4
12 1([3:0]) bitfield number of bytes per sample. Practically 1 or 2
13 1 unsigned integer number of effective bits per sample. Practically 8 to 16
14 2 unsigned integer UDP expected payload size
16 4 unsigned integer Number of I/Q samples in one hardware block
20 2 unsigned integer Number of hardware blocks in the frame
22 4 unsigned integer total number of bytes in the frame
26 4 unsigned integer Seconds of Unix timestamp at the beginning of the sending processing
30 4 unsigned integer Microseconds of Unix timestamp at the beginning of the sending processing
34 8 unsigned integer 64 bit CRC of the above
42 8 unsigned integer 64 bit CRC of the data that follows. Only in the compressed case for now.

Total size is 42 bytes including the 8 bytes CRC.

I/Q data blocks

When the stream is uncompressed UDP blocks of the payload size are stuffed with complete I/Q samples leaving a possible unused gap of less than an I/Q sample at the end of the block. The last block is filled only with the remainder samples. The number of maximally filled blocks and remainder samples in the last block is given in the "meta" data. Of course as the data stream is uncompressed these values can also be calculated from the total number of samples and the payload size.

When the stream is compressed UDP blocks are stuffed completely with bytes of the compressed stream. The last block being filled only with the remainder bytes. The number of full blocks and remainder bytes is given in the "meta" block and these values cannot be calculated otherwise.

Summary diagrams

Uncompressed stream

hardware block (2 byte I or Q samples):
|I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q|

UDP block (22 bytes):
|xxxxxxxxxxxxxxxxxxxxxx|

Frame:
|Meta:xxxxxxxxxxxxxxxxx|I/Q:I/Q:I/Q:I/Q:I/Q:xx|I/Q:I/Q:I/Q:I/Q:I/Q:xx|I/Q:I/Q:I/Q:xxxxxxxxxx|

Number of samples in a hardware block: 13
Number of blocks in a frame..........:  1 (always if uncompressed)
Number of bytes in a frame...........: 52 (4 * 13)
Complete blocks......................:  2 (calculated)
Remainder samples....................:  3 (calculated)

Compressed stream

2 hardware blocks (2 byte I or Q samples) to be sent in one frame:
|I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q|
|I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q:I/Q|

compressed block:
|yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy|

UDP block (22 bytes):
|xxxxxxxxxxxxxxxxxxxxxx|

Frame:
|Meta:xxxxxxxxxxxxxxxxx|yyyyyyyyyyyyyyyyyyyyyy|yyyyyyyyyyyyyyyyyyyyyy|yyyyyyyyyyyyyyyyy:xxxx|

Number of samples in a hardware block: 13
Number of blocks in a frame..........:  2
Number of bytes in a frame...........: 61 (2 * 22 + 17)
Complete blocks......................:  2 (calculated)
Remainder bytes......................: 17 (calculated)

GNUradio supoort

A source block is available in the gr-sdrdaemon subdirectory. This subdirectory is a complete OOT module that can be built independently following GNUradio standards. Please refer to the documentation found in this directory for further information.

License

SDRdaemon, copyright (C) 2015-2016, Edouard Griffiths, F4EXB

This program 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 2 of the License, or (at your option) any later version.

This program 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 this program; if not, see http://www.gnu.org/licenses/gpl-2.0.html