patternAzimuth

System object: phased.CustomMicrophoneElement
Package: phased

Plot custom microphone element directivity or pattern versus azimuth

Syntax

patternAzimuth(sElem,FREQ)
patternAzimuth(sElem,FREQ,EL)
patternAzimuth(sElem,FREQ,EL,Name,Value)
PAT = patternAzimuth(___)

Description

patternAzimuth(sElem,FREQ) plots the 2-D element directivity pattern versus azimuth (in dBi) for the element sElem at zero degrees elevation angle. The argument FREQ specifies the operating frequency.

patternAzimuth(sElem,FREQ,EL), in addition, plots the 2-D element directivity pattern versus azimuth (in dBi) at the elevation angle specified by EL. When EL is a vector, multiple overlaid plots are created.

patternAzimuth(sElem,FREQ,EL,Name,Value) plots the element pattern with additional options specified by one or more Name,Value pair arguments.

PAT = patternAzimuth(___) returns the element pattern. PAT is a matrix whose entries represent the pattern at corresponding sampling points specified by the 'Azimuth' parameter and the EL input argument.

Input Arguments

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Custom microphone element, specified as a phased.CustomMicrophoneElement System object.

Example: sElem = phased.CustomMicrophoneElement;

Frequency for computing directivity and pattern, specified as a positive scalar. Frequency units are in hertz.

  • For an antenna or microphone element, FREQ must lie within the range of values specified by the FrequencyRange or the FrequencyVector property of the element. Otherwise, the element produces no response and the directivity is returned as –Inf. Most elements use the FrequencyRange property except for phased.CustomAntennaElement and phased.CustomMicrophoneElement, which use the FrequencyVector property.

  • For an array of elements, FREQ must lie within the frequency range of the elements that make up the array. Otherwise, the array produces no response and the directivity is returned as –Inf.

Example: 1e8

Data Types: double

Elevation angles for computing sensor or array directivities and patterns, specified as a 1-by-N real-valued row vector. The quantity N is the number of requested elevation directions. Angle units are in degrees. The elevation angle must lie between –90° and 90°.

The elevation angle is the angle between the direction vector and the xy plane. When measured toward the z-axis, this angle is positive.

Example: [0,10,20]

Data Types: double

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Displayed pattern type, specified as the comma-separated pair consisting of 'Type' and one of

  • 'directivity' — directivity pattern measured in dBi.

  • 'efield' — field pattern of the sensor or array. For acoustic sensors, the displayed pattern is for the scalar sound field.

  • 'power' — power pattern of the sensor or array defined as the square of the field pattern.

  • 'powerdb' — power pattern converted to dB.

Example: 'powerdb'

Data Types: char

Azimuth angles, specified as the comma-separated pair consisting of 'Azimuth' and a 1-by-P real-valued row vector. Azimuth angles define where the array pattern is calculated.

Example: 'Azimuth',[-90:2:90]

Data Types: double

Output Arguments

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Element directivity or pattern, returned as an P-by-N real-valued matrix. The dimension P is the number of azimuth values determined by the 'Azimuth' name-value pair argument. The dimension N is the number of elevation angles, as determined by the EL input argument.

Examples

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Plot the azimuth directivity pattern of a custom cardioid microphone at both 0 and 30 degrees elevation.

Create a custom microphone element with a cardioid pattern.

sCustMike = phased.CustomMicrophoneElement;
sCustMike.PolarPatternFrequencies = [500 1000];
sCustMike.PolarPattern = mag2db([...
    0.5+0.5*cosd(sCustMike.PolarPatternAngles);...
    0.6+0.4*cosd(sCustMike.PolarPatternAngles)]);

Plot the directivity at 500 Hz.

fc = 500;
patternAzimuth(sCustMike,fc,[0 30])

Plot the directivity for a reduced range of azimuth angles using the Azimuth parameter. Notice the change in scale.

fc = 500;
patternAzimuth(sCustMike,fc,[0 30],...
    'Azimuth',[-40:.1:40])

More About

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Introduced in R2015a