Struct Filter 

pub struct Filter { /* private fields */ }

Create a FIR Filter, which can be applied to signals (simply Vec<f32>).

use pluto_sdr::filter::Filter;
// arbitrary signal
let signal = vec![1., 4., -3., 5., 10., -19., -4., 10., -2., -1.];
// coeff describe a 4 point moving average
let lpf_coefficients = vec![0.25, 0.25, 0.25, 0.25];
// create the low pass filter
let lpf = Filter::new(lpf_coefficients.into());

// filter the signal
let filtered = lpf.filter_windowed(&signal);
println!("{:?}", filtered);

Implementations

impl Filter

pub fn new(coeff: Vec<f32>) -> Self

Create a new FIR Filter. coeff is of type Vec<f32> and contains the FIR Filters Coefficients: [b_0, b_1, b_2, ... ].

pub fn len(&self) -> usize

The Filter size is just the size of its coefficients

pub fn filter_windowed(&self, signal: &Vec<f32>) -> Vec<f32>

recall that windowed convolution produces a signal of length N - M + 1 where N is the length of signal 1: signal; and M is the length of signal 2: self.coeff The signal should be longer than the internal filter coefficients.

pub fn create_moving_average(size: usize) -> Self

Creates a moving average filter, where all coefficients are the same value of 1 / N, where the size of the filter is N.

pub fn create_srrc(n_half: usize, b: f32, m: usize) -> Self

Creates a Matched Filter / Square-root raised cosine filter. A Root Raised Cosine / Matched Filter has very low ISI / Inter Symbol Interference. n_half is half the length of the pulse (0,1,2…(n_half*2+1)). -> we want one sample in the middle of the pulse: sinc(0), that is why the length of this filter is always uneven. b is beta / sinc roll-off and m is the oversampling factor. (Ported from Matlab: srrc.m, see Software Receiver Design book)

Trait Implementations

impl Debug for Filter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Filter

fn eq(&self, other: &Filter) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Filter