Learn more about Signal Processing Toolbox

spectrum.mtm - Thomson multitaper spectrum

Syntax

Hs = spectrum.mtm Hs = spectrum.mtm(TimeBW) Hs = spectrum.mtm(DPSS,Concentrations) Hs = spectrum.mtm(...,CombineMethod)

Description

Hs = spectrum.mtm returns a default Thomson multitaper spectrum object, Hs that defines the parameters for the Thomson multitaper spectral estimation algorithm, which uses a linear or nonlinear combination of modified periodograms. The periodograms are computed using a sequence of orthogonal tapers (windows in the frequency domain) specified from discrete prolate spheroidal sequences (dpss). This object uses the following default values:

Property Name	Default Value	Description
`TimeBW`	`4`	Product of time and bandwidth for the discrete prolate spheroidal sequences (or Slepian sequences) used as data windows
`CombineMethod`	`'adaptive'`	Algorithm for combining the individual spectral estimates. Valid values are `'adaptive'` — adaptive (nonlinear) `'unity'` — unity weights (linear) `'eigenvector'` — Eigenvalue weights (linear)

Hs = spectrum.mtm(TimeBW) returns a spectrum object, Hs with the specified time-bandwidth product.

Hs = spectrum.mtm(DPSS,Concentrations) returns a spectrum object, Hs with the specified dpss data tapers and their concentrations.

Note You can either specify the time-bandwidth product (TimeBW) or the DPSS data tapers and their Concentrations. See dpss and pmtm for more information.

Hs = spectrum.mtm(...,CombineMethod) returns a spectrum object, Hs, with the specified method for combining the spectral estimates. Refer to the table above for valid CombineMethod values.

Examples

Define a cosine of 200 Hz, add noise and view its power spectral density using the Thomson multitaper algorithm with a time-bandwidth product of 3.5.

Fs=1000;
t=0:1/Fs:.3;
x=cos(2*pi*t*200)+randn(size(t));
Hs=spectrum.mtm(3.5);
psd(Hs,x,'Fs',Fs)

The above example could be done by specifying the data tapers and concentrations instead of the time-bandwidth product.

Fs=1000;
t=0:1/Fs:.3;
x=cos(2*pi*t*200)+randn(size(t));
[e,v]=dpss(length(x),3.5);
Hs=spectrum.mtm(e,v);
psd(Hs,x,'Fs',Fs)

spectrum.mtm - Thomson multitaper spectrum

Syntax

Description

Examples

See Also

Recommended Products