README

📡 rtlsdr.js

Turn your Realtek RTL2832U based device into an SDR (Software Defined Radio) receiver using JavaScript.

Supports Node.js and WebUSB compatible browsers.

Requirements

Hardware

Realtek RTL2832U based USB adapter with R820T tuner chip

Software

Node.js 8.x or later + node-usb requirements
Web browser that supports WebUSB

Setup

Node.js

Install: npm i rtlsdrjs

Require: const RtlSdr = require('rtlsdrjs');

Browser

Download a rtlsdr.js build from a release.

Include rtlsdr.js in you HTML page: <script src="path/of/rtlsdr.js"></script>

Usage

let readSamples = true;

async function start() {
  //
  // request a device
  // - displays prompt in browser
  // - selects first device in Node.js
  //
  // RtlSdr.getDevices() can be used to get a list of all RTL SDR's attached to system
  //
  const sdr = await RtlSdr.requestDevice();

  //
  // open the device
  //
  // supported options are:
  // - ppm: frequency correction factor, in parts per million (defaults to 0)
  // - gain: optional gain in dB, auto gain is used if not specified
  //
  await sdr.open({
    ppm: 0.5
  });

  //
  // set sample rate and center frequency in Hz
  // - returns the actual values set
  //
  const actualSampleRate = await sdr.setSampleRate(2000000);
  const actualCenterFrequency = await sdr.setCenterFrequency(1090000000);

  //
  // reset the buffer
  //
  await sdr.resetBuffer();

  while (readSamples) {
    //
    // read some samples
    // - returns an ArrayBuffer with the specified number of samples,
    //   data is interleaved in IQ format
    //
    const samples = await sdr.readSamples(16 * 16384);

    //
    // process the samples ...
    //
  }
}

Acknowledgements

This library is based on Jacobo Tarrío's (@jtarrio) work in Google's Radio Receiver Chrome app, which used work from the RTL-SDR project. The Chrome USB API layer has been replaced with node-usb on Node.js and WebUSB when running in the browser.

License

Apache 2.0

Usage no npm install needed!