Examples
For gnuradio-companion, in examples subdirectory.
This can be ran without any hardware, you only need your computer. You can experience zero packet errors with the transmitter directly connected to demodulator, or add one of the channel models to find out what effect the impairments have on packet errors.
Running without any hardware requires a throttle block to establish sample rate. If any real SDR hardware is sourcing or sinking samples, then throttle isn't necessary.
When modulator is connected to demodulator without impairment block, unrealistic bitrates or frequency deviations could be achieved without experiencing errors which occur in real life. Apparently the most recent impairment blocks (channel models etc) can apply propagation degredation such as doppler shift or Rayleigh fading, frequency offsets, sample rate offset, noise etc.
Acts as a signal/packet generator for testing other receivers. Frequency offset is shown using multiplier block driven by signal source. Some SDR hardware might show slight interfering signal when operated near the center frequency, due to zero-IF architecture of hardware. This small interference has not had any effect on packet error rate.
Acts as a signal/packet analyzer for testing other transmitters. GRC file includes two GUI scope sinks, one at sample rate for viewing the signal directly, and the other scope operating at bit rate to observe correct operation of preamble detector.
in all examples the complex-to-mag block acts as an AM detector, providing a trigger for GUI scope sinks at begin or end of packet.