node-signal-processing

Object-oriented algorithms for digital signal processing.

Table of Contents

- Overview
- Installation
- Usage
- Fft
- FirBandpassFilter
- HilbertPeakDetector
- HilbertTransformer

Overview

This package contains object-oriented algorithms for digital signal processing.

Installation

Install the package with your preferred package manager, such as:

npm install @neurodevs/node-signal-processing

or:

yarn add @neurodevs/node-signal-processing

Usage

$3

``typescript
import { Fft } from '@neurodevs/node-signal-processing'

function runFftForwardAndInverse() {
const signal = [1, 2, 3, 4]

const fft = Fft.Create({ radix: signal.length })
const frequencies = fft.forward(signal)
const original = fft.inverse(frequencies)
}
`

$3

`typescript
import { FirBandpassFilter } from '@neurodevs/node-signal-processing'

function filterLowAndHighFrequenciesFromPpgSignal() {

const rawPpgSignal: number[] = [...]

const filter = FirBandpassFilter.Create({
sampleRate: 64, // PPG sample rate
lowCutoffHz: 0.4, // Filter under 24 bpm heart rate
highCutoffHz: 4.0, // Filter over 240 bpm heart rate
numTaps: 4 64 + 1, // Heuristic: 4 sampleRate + 1
attenuation: 50 // Frequencies outside bandpass reduced by 50 dB
})

const filteredPpgSignal = filter.run(rawPpgSignal)
}
`

$3

`typescript
import { HilbertPeakDetector } from '@neurodevs/node-signal-processing'

function detectPpgPeaksFromFilteredSignal() {
const filteredPpgSignal: number[] = [...] // See FirBandpassFilter example
const timestamps: number[] = [...] // Must be same length as filteredPpgSignal

const detector = HilbertPeakDetector.Create()
const results = detector.run(filteredPpgSignal, timestamps)
}
`

$3

`typescript
import { HilbertTransformer } from '@neurodevs/node-signal-processing'

function calculateAnalyticSignalAndEnvelopeFromSignal() {
const signal = [1, 2, 3, 4]

const transformer = HilbertTransformer.Create()
const { analyticSignal, envelope } = transformer.run(signal)
}
``