spectroplot

Spectroplot: I/Q Spectrogram Plot JS library.

A library to visualize the I/Q or audio spectrogram of sample data in a HTML canvas. For an example open https://triq.org/iqs and drop your sample data in.

You can choose the FFT bin number and zoom (x1, x2, x4, x8) with horizontal scrolling. There is a frequency scale and a time scale, and dB(fs) range, a histogram of the plotted dB range and the full dB range. You can choose the gain and dB range. Also an experimental (spark line type) bar with min/max dB per sample. A cross hair with info on the frequency and time position is available on hover or touch. There are some windowing functions (Rectangular, Bartlett, Hamming, Hann, Blackman, Blackman-Harris), and some Colormap (Cube1, Sox, Naive, Viridis, Plasma, Inferno, Magma, Hot, Afmhot, Gist_heat, Parabola) to choose from.

Supported raw SDR data file types are:

• .cu4
• .cs4
• .cu8 (.data .complex16u)
• .cs8 (.complex16s)
• .cu12
• .cs12
• .cu16
• .cs16
• .cu32
• .cs32
• .cu64
• .cs64
• .cf32 (.cfile .complex)
• .cf64

Also supported are (stereo) audio files containing I/Q data (if supported by the browser):

• .wav
• .bwf
• .webm
• .ogg
• .opus
• .flac
• .mp4
• .m4a
• .aac
• .mp3

All comments and suggestions very welcome.

If you like to give feedback:

• Is this useful to you? Why not, what is missing?
• Is this bundled in a useful way? Do you want the lib hosted on a CDN?

Getting Started

To use this lib you either need the worker as spectroplot.worker.js in the lib location or you need to pass the worker location or the Worker to the Spectroplot constructor.

With Webpack 4, you'll need to install worker-loader:

npm install worker-loader --save-dev

or

yarn add worker-loader --dev

then bundle the worker to some file:

import SpectroplotWorker from 'worker-loader?filename=js/spectroplot.[hash].worker.js!spectroplot/lib/worker.js'
import { Spectroplot } from 'spectroplot'

With Webpack 5 use something like:

const SpectroplotWorker = Worker(new URL('spectroplot/lib/worker.js', import.meta.url))
import { Spectroplot } from 'spectroplot'

You likely want to include some minimal styles, see styles.css:

import 'spectroplot/lib/styles.css'

then later pass the Worker to the constructor:

let spectroplot = new Spectroplot({
    workerOrUrl: SpectroplotWorker,
    // ...
})

You can also eagerly load the worker by using startWorkers():

import SpectroplotWorker from 'worker-loader?filename=js/spectroplot.[hash].worker.js!spectroplot/lib/worker.js'
import { Spectroplot, startWorkers } from 'spectroplot'
// start workers eagerly:
startWorker(SpectroplotWorker) // no need to pass a worker option to `new Spectroplot()` now

Using the API

There is a simple API which manages a drop zone and creates spectrograms from a template, see example.html for this new EasyCloning(elementOrSelector) API.

For more control construct each new Spectroplot(options) as needed with custom options. Then on the instance use setOption(opt, value), setOptions(opts), and setData(filedata). See iqspectrovue for a full featured example using VueJS.

The full API is detailed in API.md

Copyright and Licence

Copyright (C) 2017-2021 Christian W. Zuckschwerdt [e-mail]

Unless otherwise noted all sources are:

License: GPL-2+