plotSpectrum

System object: phased.MUSICEstimator
Namespace: phased

Plot MUSIC spectrum

Syntax

plotSpectrum(estimator)
output_args = plotSpectrum(estimator,Name=Value)
lh = plotSpectrum(___)


Description

plotSpectrum(estimator) plots the MUSIC spectrum computed by the most recent execution of the phased.MUSICEstimator System object™, estimator.

output_args = plotSpectrum(estimator,Name=Value) plots the MUSIC spatial spectrum with additional options specified by one or more Name=Value pair arguments.

lh = plotSpectrum(___) returns the line handle to the figure.

Input Arguments

estimator — MUSIC estimator

phased.MUSICEstimator System object.

MUSIC estimator, specified as a phased.MUSICEstimator System object

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Unit — Units used for plotting

"db" (default) | "mag" | "pow"

Units used for plotting, specified as the equal sign separated pair consisting of "Unit" and "db", "mag", or "pow".

Data Types: char

NormalizeResponse — Plot normalized spectrum

false (default) | true

Plot a normalized spectrum, specified as the equal sign separated pair consisting of "NormalizedResponse" and false or true. Normalization sets the magnitude of the largest spectrum value to one.

Data Types: char

Title — Title of plot

"MUSIC Spatial Spectrum" (default) | character vector

Title of plot, specified as an equal sign separated pair consisting of "Title" and a character vector.

Example: true

Data Types: char

Output Arguments

lh — Line handle of plot

line handle

Line handle of plot.

Examples

Plot MUSIC Spectrum of Two Signals Arriving at ULA

Estimate the DOAs of two signals received by a standard 10-element ULA having an element spacing of 1 meter. Then plot the MUSIC spectrum.

Create a ULA array object. The antenna operating frequency is 150 MHz.

fc = 150.0e6;
array = phased.ULA(NumElements=10,ElementSpacing=1.0);

Create the arriving signals at the ULA. The true direction of arrival of the first signal is 10° in azimuth and 20° in elevation. The direction of the second signal is 60° in azimuth and -5° in elevation.

fs = 8000.0;
t = (0:1/fs:1).';
sig1 = cos(2*pi*t*300.0);
sig2 = cos(2*pi*t*400.0);
sig = collectPlaneWave(array,[sig1 sig2],[10 20; 60 -5]',fc);
noise = 0.1*(randn(size(sig)) + 1i*randn(size(sig)));

Estimate the DOAs.

estimator = phased.MUSICEstimator(SensorArray=array,...
    OperatingFrequency=fc,...
    DOAOutputPort=true,NumSignalsSource="Property",...
    NumSignals=2);
[y,doas] = estimator(sig + noise);
doas = broadside2az(sort(doas),[20 -5])

doas = 1×2

    9.5829   60.3813

Plot the MUSIC spectrum.

plotSpectrum(estimator,NormalizeResponse=true)

Version History

Introduced in R2016b