Crate wavegen

Expand description

Rust waveform generator, with no_std support.

Quickstart

use wavegen::{Waveform, sine, dc_bias, sawtooth};

// Define a Waveform with 200Hz sampling rate and three function components,
// choosing f32 as the ouput type:
let wf = Waveform::<f32>::with_components(
    200.0,
    vec![sine!(50, 10), sawtooth!(20), dc_bias!(-5)]
);

// Use Waveform as an infinite iterator:
let two_seconds_of_samples: Vec<f32> = wf.iter().take(400).collect();

Look into macros section for a complete list of defined periodic functions and their constructors.

Custom periodic functions

Supported, of course. Just define your custom function as Box<Fn(f64) -> f64> and use it with Waveform.

use wavegen::Waveform;

let wf = Waveform::<f64>::with_components(100.0, vec![Box::new(|x| x % 2 as f64)]);

As Waveform can be composed of multiple components, it is possible for it to overflow during samples collection. If overflow occurs, the sample’s value will be clamped to the largest possible representation of sample’s type.

That means +/- Inf for floating point types, and MAX/MIN for integers.

use wavegen::{Waveform, dc_bias};

let wf = Waveform::<f64>::with_components(100.0, vec![dc_bias![f64::MAX], dc_bias![f64::MAX]]);
let sample = wf.iter().take(1).collect::<Vec<_>>()[0];

assert_eq!(sample, f64::INFINITY);

use wavegen::{Waveform, dc_bias};

let wf = Waveform::<i32>::with_components(100.0, vec![dc_bias![f64::MAX], dc_bias![f64::MAX]]);
let sample = wf.iter().take(1).collect::<Vec<_>>()[0];

assert_eq!(sample, i32::MAX);

Iterator panics

The WaveformIterator::next() method can panic in some rare cases if it is not able to convert the inner sample type f64 into the target sample type.

use wavegen::{Waveform, dc_bias};

let wf = Waveform::<i32>::with_components(100.0, vec![dc_bias![f64::NAN]]);

// 'f64::NAN` can't be converted into `i32`, code below will panic
let sample = wf.iter().take(1).collect::<Vec<_>>()[0];

use wavegen::{Waveform, dc_bias};

let wf = Waveform::<f32>::with_components(100.0, vec![dc_bias![f64::NAN]]);

// This however is fine, as `f64::NAN` can be represented as `f32::NAN`
let sample = wf.iter().take(1).collect::<Vec<_>>()[0];

It is probably a good practice to sanitize the parameters of the periodic function before it is constructed.

Note about Nyquist-Shannon rule enforcement

As a rule of thumb in signal processing, the sampling frequency should be at least 2 times bigger than the highest frequency of sampled continous signal.

This lib will not enforce the Nyquist-Shannon rule on the waveforms you create, therefore abominations like this are possible (altough not recommended):

use wavegen::{Waveform, sine};

// 100 Hz sampling of 80 Hz sine... will not yield realistic results.
let wf = Waveform::<f32>::with_components(100.0, vec![sine!(80)]);