Struct PsdCascade 

pub struct PsdCascade<const N: usize> { /* private fields */ }

Online power spectral density estimation

This performs efficient long term power spectral density monitoring in real time. The idea is to perform FFTs over relatively short windows and simultaneously decimate the time domain data, everything in multiple stages, then stitch together the FFT bins from the different stages. This allows arbitrarily large effective FFTs sizes in practice with only logarithmically increasing memory and cpu consumption. And it makes available PSD data from higher frequency stages immediately to get rid of the delay in recording and computing large FFTs. The effective full FFT size grows in real-time, is unlimited, and does not need to be fixed. This is well defined with the caveat that spur power (bin power not dominated by noise) depends on the stage-dependent bin width. This also typically what some modern signal analyzers or noise metrology instruments do.

See also csdl or LPSD.

Infinite averaging Incremental updates Automatic FFT stage extension

Implementations

impl<const N: usize> PsdCascade<N>

pub fn new(stage_depth: usize) -> Self

Create a new Psd instance

fft_size: size of the FFT blocks and the window stage_length: number of decimation stages. rate change per stage is 1 << stage_length detrend: Detrend method

pub fn set_avg(&mut self, avg: AvgOpts)

pub fn set_detrend(&mut self, d: Detrend)

pub fn process(&mut self, x: &[f32])

Process input items

pub fn psd(&self, opts: &MergeOpts) -> (Vec<f32>, Vec<Break>)

Return the PSD and a Vec of segement break information

Args

• min_count: minimum number of averages to include in output, if zero, also return bins that would otherwise be masked by lower stage bins.

Returns

• psd: Vec normalized reversed (Nyquist first, DC last)
• breaks: Vec of stage breaks

Trait Implementations

impl<const N: usize> Clone for PsdCascade<N>

fn clone(&self) -> PsdCascade<N>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.