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tx_sdr tool for transmitting data to SDRs, based on rtl_sdr from librtlsdr, and rx_sdr from rx_tools, using the SoapySDR vendor-neutral SDR support library, intended to support a wide range of TX-capable devices.

Warning: mostly untested pre-release

Mostly untested pre-release quality code, YMMV.


Install SoapySDR, then run:

mkdir build ; cd build
cmake ..

Tools included

After building, these binaries should then be available at the build directory:

  • tx_sdr - transmits raw I/Q data
  • pulse_gen - create I/Q data file from pulse text
  • code_gen - create I/Q data file from code text

Also some test and example programs:

  • encode_ascii - simple CLI to test ASCII encoding
  • encode_dmc - simple CLI to test DMC encoding
  • encode_hex - simple CLI to test HEX encoding
  • encode_imc - simple CLI to test IMC encoding
  • encode_mc - simple CLI to test MC encoding
  • code_dump - an example how to parse and process code text
  • example_gen - an example how to parse code text programmatically

Output formats

  • CU4 - 4-bit /channel, unsigned I/Q data (1 byte per sample)
  • CS4 - 4-bit /channel, signed I/Q data (1 byte per sample)
  • CU8 - 8-bit /channel, unsigned I/Q data
  • CS8 - 8-bit /channel, signed I/Q data
  • CU12 - 12-bit /channel, unsigned I/Q data (3 bytes per sample)
  • CS12 - 12-bit /channel, signed I/Q data (3 bytes per sample)
  • CU16 - 16-bit /channel, unsigned I/Q data
  • CS16 - 16-bit /channel, signed I/Q data
  • CU32 - 32-bit /channel, unsigned I/Q data
  • CS32 - 32-bit /channel, signed I/Q data
  • CU64 - 64-bit /channel, unsigned I/Q data
  • CS64 - 64-bit /channel, signed I/Q data
  • CF32 - 32-bit /channel, float I/Q data
  • CF64 - 64-bit /channel, double I/Q data

For CU8 (CU4) the value range is 0 to 0xff (0xf) with uniform distribution, i.e. a bias of 127.5 (7.5). This matches the output format of the RTL-SDR receivers.

For CS8 (CS4) the value range is -127 to 127 (-7 to 7) with uniform distribution, i.e. a smaller dynamic range than the unsigned formats, but without bias.

Input formats

  • CODE text
  • PULSE text
    • OOK text
    • ASK text
    • FSK text
    • PSK text
    • TONE text

Future plans

Tools to be added soon will implement modulation and encoding for:

  • OOK, ASK, AM
  • FSK, 4-FSK, GFSK, FM
  • Manchester

Device support

Currently tested with a LimeSDR-USB, LimeSDR-mini, and LimeNET Micro, but supporting all devices supported by SoapySDR is the goal. Experimental, use at your own risk, but bug reports and patches are welcome.


tx_sdr tool for transmitting data to SDRs using SoapySDR







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