System object: phased.IsotropicHydrophone
Voltage sensitivity of isotropic hydrophone
resp = step(hydrophone,freq,ang)
Instead of using the
step method to perform
the operation defined by the System object™, you can call the object
with arguments, as if it were a function. For example,
= step(obj,x) and
y = obj(x) perform
The object performs an initialization the first time the object is executed. This
initialization locks nontunable properties
and input specifications, such as dimensions, complexity, and data type of the input data.
If you change a nontunable property or an input specification, the System object issues an error. To change nontunable properties or inputs, you must first
release method to unlock the object.
freq— Voltage sensitivity frequencies
Voltage sensitivity frequencies of hydrophone, specified as a positive real scalar or a real-valued 1-by-L vector of positive values. Units are in Hz.
ang— Direction of arriving signals
Direction of arriving signals, specified as a real-valued 1-by-M row
vector or 2-by-M matrix. When
a 2-by-M matrix, each column of the matrix specifies
the direction in the form
The azimuth angle must lie between –180° and 180°,
inclusive. The elevation angle must lie between –90° and
ang is a 1-by-M row
vector, each element specifies the azimuth angle of the arriving signal.
In this case, the corresponding elevation angle is assumed to be zero.
Examine the response and patterns of an isotropic hydrophone operating between 1 kHz and 10 kHz.
Set up the hydrophone parameters. Obtain the voltage sensitivity at five different elevation angles: , , , and . All azimuth angles are at . The sensitivities are computed at the signal frequency of 2 kHz.
hydrophone = phased.IsotropicHydrophone('FrequencyRange',[1 10]*1e3); fc = 2e3; resp = hydrophone(fc,[0 0 0 0 0;-30 -15 0 15 30]);
Draw a 3-D plot of the voltage sensitivity.
pattern(hydrophone,fc,[-180:180],[-90:90],'CoordinateSystem','polar', ... 'Type','powerdb')
Examine the response and patterns of an isotropic hydrophone at three different frequencies. The hydrophone operates between 1 kHz and 10 kHz. Specify the voltage sensitivity as a vector.
Set up the hydrophone parameters and obtain the voltage sensitivity at 45° azimuth and 30° elevation. Compute the sensitivities at the signal frequencies of 2, 5, and 7 kHz.
hydrophone = phased.IsotropicHydrophone('FrequencyRange',[1 10]*1e3, ... 'VoltageSensitivity',[-100 -90 -100]); fc = [2e3 5e3 7e3]; resp = hydrophone(fc,[45;30])
resp = 1×3 14.8051 29.2202 24.4152
Draw a 2-D plot of the voltage sensitivity as a function of azimuth.
The total sensitivity of a hydrophone is a combination of its
frequency sensitivity and spatial sensitivity.
both sensitivities using nearest neighbor interpolation, and then
multiplies the sensitivities to form the total sensitivity.