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patternAzimuth

System object: phased.IsotropicHydrophone
Package: phased

Plot isotropic hydrophone directivity and response patterns versus azimuth

Syntax

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

Description

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

patternAzimuth(hydrophone,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(hydrophone,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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Isotropic hydrophone, specified as a phased.IsotropicHydrophone System object.

Example: phased.IsotropicHydrophone

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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Examine the azimuth pattern of an isotropic hydrophone at 30° elevation. The frequency range is between 1 kHz and 10 kHz. Specify the voltage sensitivity as a vector.

First, set up the hydrophone parameters.

fc = 3e3;
hydrophone = phased.IsotropicHydrophone('FrequencyRange',[1,10]*1e3, ...
    'VoltageSensitivity',[-100,-90,-100]);
patternAzimuth(hydrophone,fc,30)

Plot a smaller range of azimuth angles using the Azimuth parameter.

patternAzimuth(hydrophone,fc,30,'Azimuth',[-20:20])

More About

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Introduced in R2017a