sdrangel/plugins/samplesource/audioinput
..
CMakeLists.txt
audioinput.cpp
audioinput.h
audioinputgui.cpp
audioinputgui.h
audioinputgui.ui
audioinputplugin.cpp
audioinputplugin.h
audioinputsettings.cpp
audioinputsettings.h
audioinputwebapiadapter.cpp
audioinputwebapiadapter.h
audioinputworker.cpp
audioinputworker.h
readme.md

readme.md

Audio input plugin

Introduction

This input sample source plugin gets its samples from an audio device.

Interface

Audio input plugin GUI

1: Start/Stop

Device start / stop button.

  • Blue triangle icon: device is ready and can be started
  • Green square icon: device is running and can be stopped
  • Magenta (or pink) square icon: an error occurred. In the case the device was accidentally disconnected you may click on the icon, plug back in and start again.

2: Device

The audio device to use.

3: Refresh devices

Refresh the list of audio devices.

4: Audio sample rate

Audio sample rate in Hz (Sa/s).

5: Decimation

A decimation factor to apply to the audio data. The baseband sample rate will be the audio sample, divided by this decimation factor.

6: Volume

A control to set the input volume. This is not supported by all input audio devices.

7: Channel Map

This controls how the left and right audio channels map on to the IQ channels.

  • Mono L - Real samples are taken from the left audio channel and are heterodyned by the fourth of the sample rate (fs/4) to obtain complex samples. Therefore the spectrum of the complex baseband is centered at the fourth of the sample rate (fs/4). As per Nyquist rule only a bandwidth of half of the sample rate (fs/2) is available for real signals. Frequencies outside the [0, fs/2] interval are artefacts and can be eliminated by decimating by a factor of 2.
  • Mono R - Same as above but takes the right audio channel for the real signal.
  • I=L, Q=R - The left audio channel is driven to the I channel. The right audio channel is driven to the Q channel for a complex (analytic signal)input.
  • I=R, Q=L - The right audio channel is driven to the I channel. The left audio channel is driven to the Q channel for a complex (analytic signal)input.