UTILSLIB::WelchPsd Class Reference

Welch's averaged-periodogram power spectral density estimator. More...

#include <welch_psd.h>

Public Types
enum	WindowType { Hann =0 , Hamming =1 , Blackman =2 , FlatTop =3 }

Static Public Member Functions
static WelchPsdResult	compute (const Eigen::MatrixXd &matData, double dSFreq, int iNfft=256, double dOverlap=0.5, WindowType window=Hann, const Eigen::RowVectorXi &vecPicks=Eigen::RowVectorXi())
static Eigen::RowVectorXd	computeVector (const Eigen::RowVectorXd &vecData, double dSFreq, int iNfft=256, double dOverlap=0.5, WindowType window=Hann)
static Eigen::RowVectorXd	freqAxis (int iNfft, double dSFreq)

Detailed Description

Welch's averaged-periodogram power spectral density estimator.

Divides each channel into overlapping windowed segments, computes the FFT of each segment, and averages the squared magnitudes. The result is a one-sided PSD normalised so that integrating over frequency recovers the mean signal power.

// 600 Hz data, 512-sample FFT, 50 % overlap, Hann window
WelchPsdResult r = WelchPsd::compute(matData, 600.0, 512);
// r.matPsd   → n_channels × 257
// r.vecFreqs → [0, 1.17, 2.34, …, 300] Hz

Definition at line 84 of file welch_psd.h.

Member Enumeration Documentation

WindowType

enum UTILSLIB::WelchPsd::WindowType

Window function applied to each segment before the FFT.

Enumerator
Hann
Hamming
Blackman
FlatTop

Definition at line 88 of file welch_psd.h.

Member Function Documentation

compute()

WelchPsdResult WelchPsd::compute ( const Eigen::MatrixXd & matData, double dSFreq, int iNfft = 256, double dOverlap = 0.5, WindowType window = Hann, const Eigen::RowVectorXi & vecPicks = Eigen::RowVectorXi() )

static

Compute Welch PSD for every (selected) channel of a data matrix.

Parameters

[in]	matData	Data matrix (n_channels × n_samples).
[in]	dSFreq	Sampling frequency in Hz.
[in]	iNfft	FFT length / segment length in samples (default 256).
[in]	dOverlap	Fractional overlap between adjacent segments, in [0, 1) (default 0.5).
[in]	window	Window function (default Hann).
[in]	vecPicks	Channel row indices to process; empty = all channels.

Returns

WelchPsdResult with matPsd (n_picks × iNfft/2+1) and vecFreqs.

Definition at line 164 of file welch_psd.cpp.

computeVector()

RowVectorXd WelchPsd::computeVector ( const Eigen::RowVectorXd & vecData, double dSFreq, int iNfft = 256, double dOverlap = 0.5, WindowType window = Hann )

static

Compute Welch PSD for a single channel row vector.

Parameters

[in]	vecData	Single-channel data (1 × n_samples row vector).
[in]	dSFreq	Sampling frequency in Hz.
[in]	iNfft	FFT / segment length in samples.
[in]	dOverlap	Fractional segment overlap in [0, 1).
[in]	window	Window function.

Returns

One-sided PSD row vector of length iNfft/2+1.

Definition at line 117 of file welch_psd.cpp.

freqAxis()

RowVectorXd WelchPsd::freqAxis ( int iNfft, double dSFreq )

static

Build the frequency axis for a given FFT length and sampling frequency.

Parameters

[in]	iNfft	FFT length.
[in]	dSFreq	Sampling frequency in Hz.

Returns

Row vector of length iNfft/2+1 with frequencies in Hz.

Definition at line 106 of file welch_psd.cpp.

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The documentation for this class was generated from the following files:

• src/libraries/dsp/welch_psd.h
• src/libraries/dsp/welch_psd.cpp