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Signal Processing Toolbox Functions

Alphabetical List By Category

Signal Generation and Preprocessing

Smoothing and Denoising

detrendRemove linear trends
filloutliersDetect and replace outliers in data
hampelOutlier removal using Hampel identifier
isoutlierFind outliers in data
medfilt11-D median filtering
movmadMoving median absolute deviation
movmedianMoving median
sgolaySavitzky-Golay filter design
sgolayfiltSavitzky-Golay filtering
smoothdataSmooth noisy data

Resampling

decimateDecimation — decrease sampling rate
downsampleDecrease sampling rate by integer factor
fillgapsFill gaps using autoregressive modeling
fillmissingFill missing values
interpInterpolation — increase sampling rate by integer factor
interp11-D data interpolation (table lookup)
pchipPiecewise Cubic Hermite Interpolating Polynomial (PCHIP)
resampleResample uniform or nonuniform data to new fixed rate
splineCubic spline data interpolation
upfirdnUpsample, apply FIR filter, and downsample
upsampleIncrease sampling rate by integer factor

Waveform Generation

chirpSwept-frequency cosine
diricDirichlet or periodic sinc function
gauspulsGaussian-modulated sinusoidal pulse
gmonopulsGaussian monopulse
pulstranPulse train
randnNormally distributed random numbers
rectpulsSampled aperiodic rectangle
sawtoothSawtooth or triangle wave
sinSine of argument in radians
sincSinc function
squareSquare wave
stemPlot discrete sequence data
tripulsSampled aperiodic triangle
vcoVoltage controlled oscillator
bufferBuffer signal vector into matrix of data frames
demodDemodulation for communications simulation
modulateModulation for communications simulation
seqperiodCompute period of sequence
shiftdataShift data to operate on specified dimension
unshiftdataInverse of shiftdata
stripsStrip plot
udecodeDecode 2n-level quantized integer inputs to floating-point outputs
uencodeQuantize and encode floating-point inputs to integer outputs
marcumqGeneralized Marcum Q function

Measurements and Feature Extraction

Descriptive Statistics

cummaxCumulative maximum
cumminCumulative minimum
envelopeSignal envelope
maxLargest elements in array
meanAverage or mean value of array
meanfreqMean frequency
medfreqMedian frequency
medianMedian value of array
minSmallest elements in array
movmadMoving median absolute deviation
movmedianMoving median
peak2peakMaximum-to-minimum difference
peak2rmsPeak-magnitude-to-RMS ratio
rmsRoot-mean-square level
rssq Root-sum-of-squares level
seqperiodCompute period of sequence
stdStandard deviation
varVariance
alignsignalsAlign two signals by delaying earliest signal
cusumDetect small changes in mean using cumulative sum
dtwDistance between signals using dynamic time warping
edrEdit distance on real signals
findchangeptsFind abrupt changes in signal
finddelayEstimate delay(s) between signals
findpeaksFind local maxima
findsignalFind signal location using similarity search

Pulse and Transition Metrics

dutycycle Duty cycle of pulse waveform
midcrossMid-reference level crossing for bilevel waveform
pulseperiodPeriod of bilevel pulse
pulsesepSeparation between bilevel waveform pulses
pulsewidthBilevel waveform pulse width
statelevels State-level estimation for bilevel waveform with histogram method
falltime Fall time of negative-going bilevel waveform transitions
overshoot Overshoot metrics of bilevel waveform transitions
risetime Rise time of positive-going bilevel waveform transitions
settlingtimeSettling time for bilevel waveform
slewrateSlew rate of bilevel waveform
undershoot Undershoot metrics of bilevel waveform transitions

Spectral Measurements

bandpowerBand power
enbwEquivalent noise bandwidth
meanfreqMean frequency
medfreqMedian frequency
obwOccupied bandwidth
powerbwPower bandwidth
sfdrSpurious free dynamic range
sinadSignal to noise and distortion ratio
snrSignal-to-noise ratio
thdTotal harmonic distortion
toiThird-order intercept point

Correlation and Convolution

corrcoefCorrelation coefficients
corrmtxData matrix for autocorrelation matrix estimation
xcorrCross-correlation
xcorr22-D cross-correlation
xcovCross-covariance
cconvModulo-N circular convolution
convConvolution and polynomial multiplication
conv22-D convolution
convmtxConvolution matrix
covCovariance
deconvDeconvolution and polynomial division
alignsignalsAlign two signals by delaying earliest signal
dtwDistance between signals using dynamic time warping
edrEdit distance on real signals
finddelayEstimate delay(s) between signals
findsignalFind signal location using similarity search

Digital and Analog Filters

Digital Filter Design

butterButterworth filter design
buttordButterworth filter order and cutoff frequency
cheby1Chebyshev Type I filter design
cheb1ordChebyshev Type I filter order
cheby2Chebyshev Type II filter design
cheb2ordChebyshev Type II filter order
designfiltDesign digital filters
ellipElliptic filter design
ellipordMinimum order for elliptic filters
polyscaleScale roots of polynomial
polystabStabilize polynomial
yulewalkRecursive digital filter design
cfirpmComplex and nonlinear-phase equiripple FIR filter design
designfiltDesign digital filters
fir1Window-based FIR filter design
fir2Frequency sampling-based FIR filter design
firclsConstrained-least-squares FIR multiband filter design
fircls1Constrained-least-squares linear-phase FIR lowpass and highpass filter design
firlsLeast-squares linear-phase FIR filter design
firpmParks-McClellan optimal FIR filter design
firpmordParks-McClellan optimal FIR filter order estimation
gaussdesignGaussian FIR pulse-shaping filter design
intfiltInterpolation FIR filter design
kaiserordKaiser window FIR filter design estimation parameters
maxflatGeneralized digital Butterworth filter design
rcosdesignRaised cosine FIR pulse-shaping filter design
sgolaySavitzky-Golay filter design
digitalFilterDigital filter
doubleCast coefficients of digital filter to double precision
dspfwizCreate Simulink filter block using Realize Model panel
filt2blockGenerate Simulink filter block
fvtoolOpen Filter Visualization Tool
infoInformation about digital filter
isdoubleDetermine if digital filter coefficients are double precision
issingleDetermine if digital filter coefficients are single precision
singleCast coefficients of digital filter to single precision

Digital Filter Analysis

absAbsolute value (magnitude)
anglePhase angle
freqzFrequency response of digital filter
grpdelayAverage filter delay (group delay)
phasedelayPhase delay of digital filter
phasezPhase response of digital filter
unwrapCorrect phase angles to produce smoother phase plots
zerophaseZero-phase response of digital filter
zplaneZero-pole plot
impzImpulse response of digital filter
impzlengthImpulse response length
stepzStep response of digital filter
filtordFilter order
filternorm 2-norm or infinity-norm of digital filter
firtypeType of linear phase FIR filter
isallpassDetermine whether filter is allpass
isfirDetermine if digital filter has finite impulse response
islinphaseDetermine whether filter has linear phase
ismaxphaseDetermine whether filter is maximum phase
isminphaseDetermine whether filter is minimum phase
isstableDetermine whether filter is stable
fvtoolOpen Filter Visualization Tool

Digital Filtering

fftfiltFFT-based FIR filtering using overlap-add method
filterFilter data with recursive (IIR) or nonrecursive (FIR) filter
filter22-D digital filter
filtfiltZero-phase digital filtering
filticInitial conditions for transposed direct-form II filter implementation
hampelOutlier removal using Hampel identifier
latcfiltLattice and lattice-ladder filter implementation
medfilt11-D median filtering
residuezZ-transform partial-fraction expansion
sgolayfiltSavitzky-Golay filtering
sosfiltSecond-order (biquadratic) IIR digital filtering
convConvolution and polynomial multiplication
conv22-D convolution
convmtxConvolution matrix
deconvDeconvolution and polynomial division
cell2sosConvert second-order sections cell array to matrix
eqtflengthEqualize lengths of transfer function's numerator and denominator
latc2tfConvert lattice filter parameters to transfer function form
sos2cellConvert second-order sections matrix to cell array
sos2ssConvert digital filter second-order section parameters to state-space form
sos2tfConvert digital filter second-order section data to transfer function form
sos2zpConvert digital filter second-order section parameters to zero-pole-gain form
ssConvert digital filter to state-space representation
ss2sosConvert digital filter state-space parameters to second-order sections form
ss2tfConvert state-space representation to transfer function
ss2zpConvert state-space filter parameters to zero-pole-gain form
tfConvert digital filter to transfer function
tf2latcConvert transfer function filter parameters to lattice filter form
tf2sosConvert digital filter transfer function data to second-order sections form
tf2ssConvert transfer function filter parameters to state-space form
tf2zpConvert transfer function filter parameters to zero-pole-gain form
tf2zpkConvert transfer function filter parameters to zero-pole-gain form
zp2sosConvert zero-pole-gain filter parameters to second-order sections form
zp2ssConvert zero-pole-gain filter parameters to state-space form
zp2tfConvert zero-pole-gain filter parameters to transfer function form
zpkConvert digital filter to zero-pole-gain representation
dspfwizCreate Simulink filter block using Realize Model panel
filt2blockGenerate Simulink filter block

Multirate Signal Processing

decimateDecimation — decrease sampling rate
downsampleDecrease sampling rate by integer factor
fillgapsFill gaps using autoregressive modeling
interpInterpolation — increase sampling rate by integer factor
interp11-D data interpolation (table lookup)
pchipPiecewise Cubic Hermite Interpolating Polynomial (PCHIP)
resampleResample uniform or nonuniform data to new fixed rate
splineCubic spline data interpolation
upfirdnUpsample, apply FIR filter, and downsample
upsampleIncrease sampling rate by integer factor

Analog Filters

besselfBessel analog filter design
butterButterworth filter design
cheby1Chebyshev Type I filter design
cheby2Chebyshev Type II filter design
ellipElliptic filter design
freqsFrequency response of analog filters
freqspaceFrequency spacing for frequency response
besselap Bessel analog lowpass filter prototype
bilinearBilinear transformation method for analog-to-digital filter conversion
buttapButterworth filter prototype
cheb1apChebyshev Type I analog lowpass filter prototype
cheb2apChebyshev Type II analog lowpass filter prototype
ellipapElliptic analog lowpass filter prototype
impinvarImpulse invariance method for analog-to-digital filter conversion
lp2bpTransform lowpass analog filters to bandpass
lp2bsTransform lowpass analog filters to bandstop
lp2hpTransform lowpass analog filters to highpass
lp2lpChange cutoff frequency for lowpass analog filter

Transforms

absAbsolute value (magnitude)
anglePhase angle
fftFast Fourier transform
ifftInverse fast Fourier transform
fftshiftShift zero-frequency component to center of spectrum
dftmtxDiscrete Fourier transform matrix
fft22-D fast Fourier transform
ifft22-D inverse fast Fourier transform
cztChirp Z-transform
goertzelDiscrete Fourier transform with second-order Goertzel algorithm
dctDiscrete cosine transform
idctInverse discrete cosine transform
envelopeSignal envelope
fwhtFast Walsh-Hadamard transform
ifwhtInverse Fast Walsh-Hadamard transform
hilbertDiscrete-time analytic signal using Hilbert transform
ccepsComplex cepstral analysis
iccepsInverse complex cepstrum
rcepsReal cepstrum and minimum phase reconstruction
bitrevorderPermute data into bit-reversed order
digitrevorderPermute input into digit-reversed order

Spectral Analysis

Spectral Estimation

cpsdCross power spectral density
findpeaksFind local maxima
mscohereMagnitude-squared coherence
periodogramPeriodogram power spectral density estimate
plombLomb-Scargle periodogram
pmtmMultitaper power spectral density estimate
pspectrumAnalyze signals in the frequency and time-frequency domains
pwelchWelch’s power spectral density estimate
tfestimateTransfer function estimate
dbConvert energy or power measurements to decibels
db2magConvert decibels to magnitude
db2powConvert decibels to power
mag2dbConvert magnitude to decibels
pow2dbConvert power to decibels

Time-Frequency Analysis

fsstFourier synchrosqueezed transform
ifsstInverse Fourier synchrosqueezed transform
pspectrumAnalyze signals in the frequency and time-frequency domains
spectrogramSpectrogram using short-time Fourier transform
tfridgeTime-frequency ridges
xspectrogramCross-spectrogram using short-time Fourier transforms

Parametric Spectral Estimation

findpeaksFind local maxima
pburgAutoregressive power spectral density estimate — Burg’s method
pcovAutoregressive power spectral density estimate — covariance method
pmcovAutoregressive power spectral density estimate — modified covariance method
pyulearAutoregressive power spectral density estimate — Yule-Walker method
dbConvert energy or power measurements to decibels
db2magConvert decibels to magnitude
db2powConvert decibels to power
mag2dbConvert magnitude to decibels
pow2dbConvert power to decibels

Subspace Methods

peigPseudospectrum using eigenvector method
pmusicPseudospectrum using MUSIC algorithm
rooteigFrequency and power content using eigenvector method
rootmusicRoot MUSIC algorithm

Windows

barthannwinModified Bartlett-Hann window
bartlettBartlett window
blackmanBlackman window
blackmanharrisMinimum 4-term Blackman-Harris window
bohmanwinBohman window
chebwinChebyshev window
enbwEquivalent noise bandwidth
flattopwinFlat top weighted window
gausswinGaussian window
hammingHamming window
hannHann (Hanning) window
kaiserKaiser window
nuttallwinNuttall-defined minimum 4-term Blackman-Harris window
parzenwinParzen (de la Vallée Poussin) window
rectwinRectangular window
taylorwinTaylor window
triangTriangular window
tukeywinTukey (tapered cosine) window
wvtoolOpen Window Visualization Tool
dpssDiscrete prolate spheroidal (Slepian) sequences
dpssclearRemove discrete prolate spheroidal sequences from database
dpssdirDiscrete prolate spheroidal sequences database directory
dpssloadLoad discrete prolate spheroidal sequences from database
dpsssaveDiscrete prolate spheroidal or Slepian sequence database

Spectral Measurements

bandpowerBand power
enbwEquivalent noise bandwidth
meanfreqMean frequency
medfreqMedian frequency
obwOccupied bandwidth
powerbwPower bandwidth
sfdrSpurious free dynamic range
sinadSignal to noise and distortion ratio
snrSignal-to-noise ratio
thdTotal harmonic distortion
toiThird-order intercept point

Signal Modeling

Autoregressive and Moving Average Models

arburgAutoregressive all-pole model parameters — Burg’s method
arcovAutoregressive all-pole model parameters — covariance method
armcovAutoregressive all-pole model parameters — modified covariance method
aryuleAutoregressive all-pole model parameters — Yule-Walker method
invfreqsIdentify continuous-time filter parameters from frequency response data
invfreqzIdentify discrete-time filter parameters from frequency response data
prony Prony method for filter design
stmcbCompute linear model using Steiglitz-McBride iteration

Linear Predictive Coding

corrmtxData matrix for autocorrelation matrix estimation
levinsonLevinson-Durbin recursion
lpcLinear prediction filter coefficients
rlevinsonReverse Levinson-Durbin recursion
schurrcCompute reflection coefficients from autocorrelation sequence
xcorrCross-correlation
xcovCross-covariance
ac2polyConvert autocorrelation sequence to prediction polynomial
ac2rcConvert autocorrelation sequence to reflection coefficients
is2rcConvert inverse sine parameters to reflection coefficients
lar2rcConvert log area ratio parameters to reflection coefficients
lsf2polyConvert line spectral frequencies to prediction filter coefficients
poly2acConvert prediction filter polynomial to autocorrelation sequence
poly2lsfConvert prediction filter coefficients to line spectral frequencies
poly2rcConvert prediction filter polynomial to reflection coefficients
rc2acConvert reflection coefficients to autocorrelation sequence
rc2isConvert reflection coefficients to inverse sine parameters
rc2larConvert reflection coefficients to log area ratio parameters
rc2polyConvert reflection coefficients to prediction filter polynomial

Vibration Analysis

envspectrumEnvelope spectrum for machinery diagnosis
orderspectrumAverage spectrum versus order for vibration signal
ordertrackTrack and extract order magnitudes from vibration signal
orderwaveformExtract time-domain order waveforms from vibration signal
rpmfreqmapFrequency-RPM map for order analysis
rpmordermapOrder-RPM map for order analysis
tachorpmExtract RPM signal from tachometer pulses
tsaTime-synchronous signal average
modalfitModal parameters from frequency-response functions
modalfrfFrequency-response functions for modal analysis
modalsdGenerate stabilization diagram for modal analysis
rainflowRainflow counts for fatigue analysis
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