LuaRadio

LuaRadio is a lightweight, embeddable flow graph signal processing framework for software-defined radio. It provides a suite of source, sink, and processing blocks, with a simple API for defining flow graphs, running flow graphs, creating blocks, and creating data types. LuaRadio is built on LuaJIT, has a small binary footprint of under 750 KB (including LuaJIT), has no external hard dependencies, and is MIT licensed.

LuaRadio can be used to rapidly prototype software radios, modulation/demodulation utilities, and signal processing experiments. It can also be embedded into existing radio applications to serve as a user scriptable engine for signal processing.

LuaRadio blocks are written in pure Lua, but can use LuaJIT’s FFI to wrap external libraries, like VOLK, liquid-dsp, and others, for computational acceleration, sophisticated processing, and interfacing with SDR hardware.

Use GNU Radio? See how LuaRadio compares to GNU Radio.

See the LuaRadio mailing list for general discussion.

Example

Wideband FM Broadcast Radio Receiver

local radio = require('radio')

radio.CompositeBlock():connect(
    radio.RtlSdrSource(88.5e6 - 250e3, 1102500), -- RTL-SDR source, offset-tuned to 88.5 MHz - 250 kHz
    radio.TunerBlock(-250e3, 200e3, 5),          -- Translate -250 kHz, filter 200 kHz, decimate 5
    radio.FrequencyDiscriminatorBlock(1.25),     -- Frequency demodulate with 1.25 modulation index
    radio.LowpassFilterBlock(128, 15e3),         -- Low-pass filter 15 kHz for L+R audio
    radio.FMDeemphasisFilterBlock(75e-6),        -- FM de-emphasis filter with 75 uS time constant
    radio.DownsamplerBlock(5),                   -- Downsample by 5
    radio.PulseAudioSink(1)                      -- Play to system audio with PulseAudio
):run()

Check out some more examples of what you can build with LuaRadio.

Quickstart

With LuaJIT installed, LuaRadio can be run directly from the repository:

git clone https://github.com/vsergeev/luaradio.git

$ cd luaradio
$ ./luaradio --platform
luajit          LuaJIT 2.0.5
os              Linux
arch            x64
page size       4096
cpu count       4
cpu model       Intel(R) Core(TM) i5-4570T CPU @ 2.90GHz
features
    fftw3f      true    fftw-3.3.8-sse2-avx
    volk        true    2.0 (avx2_64_mmx_orc)
    liquid      true    1.3.2
$

LuaRadio is accelerated by the optional libraries liquid-dsp, VOLK, and fftw for real-time applications. To run the real-time examples, install liquid-dsp or VOLK, and check that the liquid and/or volk features are marked true in the platform information.

LuaRadio primarily supports Linux. It also strives to support FreeBSD and Mac OS X, but real-time support and audio sink support on these platforms is currently experimental.

Try out one of the examples with an RTL-SDR dongle:

$ ./luaradio examples/rtlsdr_wbfm_mono.lua 91.1e6

LuaRadio and all of its examples run great on the Raspberry Pi 3 with Arch Linux.

See the Getting Started guide for a tutorial on building your own flow graphs.