Signal Processing Toolbox

Reference

This section contains detailed descriptions of all Signal Processing Toolbox functions. It begins with a list of functions grouped by subject area and continues with the reference entries in alphabetical order. For more information, see the online MATLAB Function Reference.

Waveform Generation and Plotting
chirp
Swept-frequency cosine generator.

diric
Dirichlet or periodic sinc function.

gauspuls
Gaussian-modulated sinusoidal pulse generator.

pulstran
Pulse train generator.

rectpuls
Sampled aperiodic rectangle generator.

sawtooth
Sawtooth or triangle wave generator.

sinc
Sinc or sin(t)/t function.

square
Square wave generator.

strips
Strip plot.

tripuls
Sampled aperiodic triangle generator.

Waveform Generation and Plotting
`chirp`	Swept-frequency cosine generator.
`diric`	Dirichlet or periodic sinc function.
`gauspuls`	Gaussian-modulated sinusoidal pulse generator.
`pulstran`	Pulse train generator.
`rectpuls`	Sampled aperiodic rectangle generator.
`sawtooth`	Sawtooth or triangle wave generator.
`sinc`	Sinc or sin(t)/t function.
`square`	Square wave generator.
`strips`	Strip plot.
`tripuls`	Sampled aperiodic triangle generator.


Filter Analysis and Implementation
`abs`	Absolute value (magnitude).
`angle`	Phase angle.
`conv`	Convolution and polynomial multiplication.
`conv2`	Two-dimensional convolution.
`fftfilt`	FFT-based FIR filtering using the overlap-add method.
`filter`	Filter data with a recursive (IIR) or nonrecursive (FIR) filter.
`filter2`	Two-dimensional digital filtering.
`filtfilt`	Zero-phase digital filtering.
`filtic`	Make initial conditions for filter function.
`freqs`	Frequency response of analog filters.
`freqspace`	Frequency spacing for frequency response.

`freqz`	Frequency response of digital filters.
`grpdelay`	Average filter delay (group delay).
`impz`	Impulse response of digital filters.
`latcfilt`	Lattice and lattice-ladder filter implementation.
`unwrap`	Unwrap phase angles.
`zplane`	Zero-pole plot.


Linear System Transformations
`convmtx`	Convolution matrix.
`latc2tf`	Lattice filter to transfer function conversion.
`poly2rc`	Reflection coefficients from polynomial coefficients.
`rc2poly`	Polynomial coefficients from reflection coefficients.
`residuez`	z-transform partial-fraction expansion.
`sos2ss`	Second-order section to state-space conversion.
`sos2tf`	Second-order section to transfer function conversion.
`sos2zp`	Second-order section to zero-pole-gain conversion.
`ss2sos`	State-space to second-order section conversion.
`ss2tf`	State-space to transfer function conversion.
`ss2zp`	State-space to zero-pole-gain conversion.
`tf2latc`	Transfer function to lattice filter conversion.

`tf2ss`	Transfer function to state-space conversion.
`tf2zp`	Transfer function to zero-pole-gain conversion.
`zp2sos`	Zero-pole-gain to second-order section conversion.
`zp2ss`	Zero-pole-gain to state-space conversion.
`zp2tf`	Zero-pole-gain to transfer function conversion.


IIR Filter Design--Classical and Direct
`besself`	Bessel analog filter design.
`butter`	Butterworth analog and digital filter design.
`cheby1`	Chebyshev type I filter design (passband ripple).
`cheby2`	Chebyshev type II filter design (stopband ripple).
`ellip`	Elliptic (Cauer) filter design.
`maxflat`	Generalized digital Butterworth filter design.
`yulewalk`	Recursive digital filter design.


IIR Filter Order Selection
`buttord`	Butterworth filter order selection.
`cheb1ord`	Chebyshev type I filter order selection.
`cheb2ord`	Chebyshev type II filter order selection.
`ellipord`	Elliptic filter order selection.


FIR Filter Design
`cremez`	Complex and nonlinear-phase equiripple FIR filter design
`fir1`	Window-based finite impulse response filter design--standard response.
`fir2`	Window-based finite impulse response filter design--arbitrary response.
`fircls`	Constrained least square FIR filter design for multiband filters.
`fircls1`	Constrained least square filter design for lowpass and highpass linear phase FIR filters.
`firls`	Least square linear-phase FIR filter design.
`firrcos`	Raised cosine FIR filter design.
`intfilt`	Interpolation FIR filter design.
`kaiserord`	Estimate parameters for `fir1` with Kaiser window.
`remez`	Parks-McClellan optimal FIR filter design.
`remezord`	Parks-McClellan optimal FIR filter order estimation.


Transforms
`czt`	Chirp z-transform.
`dct`	Discrete cosine transform (DCT).
`dftmtx`	Discrete Fourier transform matrix.
`fft`	One-dimensional fast Fourier transform.
`fft2`	Two-dimensional fast Fourier transform.
`fftshift`	Rearrange the outputs of `fft` and `fft2`.
`hilbert`	Hilbert transform.
`idct`	Inverse discrete cosine transform.
`ifft`	One-dimensional inverse fast Fourier transform.
`ifft2`	Two-dimensional inverse fast Fourier transform.


Statistical Signal Processing
`cohere`	Estimate magnitude squared coherence function between two signals.
`corrcoef`	Correlation coefficient matrix.
`cov`	Covariance matrix.
`csd`	Estimate the cross spectral density (CSD) of two signals.
`pmem`	Power spectrum estimate using maximum entropy method (MEM).
`pmtm`	Power spectrum estimate using the multitaper method (MTM).

`pmusic`	Power spectrum estimate using MUSIC eigenvector method.
`psd`	Estimate the power spectral density (PSD) of a signal.
`tfe`	Transfer function estimate from input and output.
`xcorr`	Cross-correlation function estimate.
`xcorr2`	Two-dimensional cross-correlation.
`xcov`	Cross-covariance function estimate (equal to mean-removed cross-correlation).


Parametric Modeling
`invfreqs`	Continuous-time (analog) filter identification from frequency data.
`invfreqz`	Discrete-time filter identification from frequency data.
`levinson`	Levinson-Durbin recursion.
`lpc`	Linear prediction coefficients.
`prony`	Prony's method for time domain IIR filter design.
`stmcb`	Linear model using Steiglitz-McBride iteration.


Specialized Operations
`cceps`	Complex cepstral analysis.
`cplxpair`	Group complex numbers into complex conjugate pairs.
`decimate`	Decrease the sampling rate for a sequence (decimation).
`deconv`	Deconvolution and polynomial division.
`demod`	Demodulation for communications simulation.
`detrend`	Remove linear trends.
`dpss`	Discrete prolate spheroidal sequences (Slepian sequences).
`dpssclear`	Remove discrete prolate spheroidal sequences from database.
`dpssdir`	Discrete prolate spheroidal sequences database directory.
`dpssload`	Load discrete prolate spheroidal sequences from database.
`dpsssave`	Save discrete prolate spheroidal sequences in database.
`icceps`	Inverse complex cepstrum.
`interp`	Increase sampling rate by an integer factor (interpolation).
`medfilt1`	One-dimensional median filtering.
`modulate`	Modulation for communications simulation.
`polystab`	Stabilize polynomial.
`rceps`	Real cepstrum and minimum phase reconstruction.
`resample`	Change sampling rate by any factor.
`specgram`	Time-dependent frequency analysis (spectrogram).
`upfirdn`	Apply FIR filter and perform sample rate conversion.
`vco`	Voltage controlled oscillator.


Analog Prototype Design
`besselap`	Bessel analog lowpass filter prototype.
`buttap`	Butterworth analog lowpass filter prototype.
`cheb1ap`	Chebyshev type I analog lowpass filter prototype.
`cheb2ap`	Chebyshev type II analog lowpass filter prototype.
`ellipap`	Elliptic analog lowpass filter prototype.


Frequency Translation
`lp2bp`	Lowpass to bandpass analog filter transformation.
`lp2bs`	Lowpass to bandstop analog filter transformation.
`lp2hp`	Lowpass to highpass analog filter transformation.
`lp2lp`	Lowpass to lowpass analog filter transformation.


Filter Discretization
`bilinear`	Map variables using bilinear transformation.
`impinvar`	Impulse invariance method of analog-to-digital filter conversion.


Interactive Tools
`sptool`	Interactive signal, filter, and spectrum analysis tool.

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