System object: phased.FrostBeamformer
Package: phased
Perform Frost beamforming
Y = step(H,X)
Y = step(H,X,XT)
Y = step(H,X,ANG)
Y = step(H,X,XT,ANG)
[Y,W] =
step(___)
Starting in R2016b, 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, y
= step(obj,x)
and y = obj(x)
perform
equivalent operations.
performs
Frost beamforming on the input, Y
= step(H
,X
)X
, and returns
the beamformed output in Y
.
uses Y
= step(H
,X
,XT
)XT
as
the training samples to calculate the beamforming weights. This syntax
is available when you set the TrainingInputPort
property
to true
.
uses Y
= step(H
,X
,ANG
)ANG
as
the beamforming direction. This syntax is available when you set the DirectionSource
property
to 'Input port'
.
combines
all input arguments. This syntax is available when you set the Y
= step(H
,X
,XT
,ANG
)TrainingInputPort
property
to true
and set the DirectionSource
property
to 'Input port'
.
[
returns the beamforming weights, Y
,W
] =
step(___)W
.
This syntax is available when you set the WeightsOutputPort
property
to true
.
The object performs an initialization the first time the step
method
is executed. This initialization locks nontunable
properties (MATLAB) 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 call the release
method
to unlock the object.

Beamformer object. 

Input signal, specified as an MbyN matrix. M must
be larger than the FIR filter length specified in the The size of the first dimension of this input matrix can vary to simulate a changing signal length, such as a pulse waveform with variable pulse repetition frequency. 

Training samples, specified as an MbyN matrix. M and N have
the same dimensions as The size of the first dimension of this input matrix can vary to simulate a changing signal length, such as a pulse waveform with variable pulse repetition frequency. 

Beamforming directions, specified as a length2 column vector.
The vector has the form 

Beamformed output. 

Beamforming weights. 
phased.FrostBeamformer
uses a beamforming algorithm
proposed by Frost. It can be considered the timedomain counterpart
of the minimum variance distortionless response (MVDR) beamformer.
The algorithm does the following:
Steers the array to the beamforming direction.
Applies an FIR filter to the output of each sensor to achieve the distortionless response constraint. The filter is specific to each sensor.
For further details, see [1].
[1] Frost, O. “An Algorithm For Linearly Constrained Adaptive Array Processing”, Proceedings of the IEEE. Vol. 60, Number 8, August, 1972, pp. 926–935.
[2] Van Trees, H. Optimum Array Processing. New York: WileyInterscience, 2002.