Y = step(H,X) performs
phase shift beamforming on the input, X, and
returns the beamformed output in Y.

Y = step(H,X,ANG) uses ANG as
the beamforming direction. This syntax is available when you set the DirectionSource property
to 'Input port'.

[Y,W] =
step(___) returns the beamforming weights, W.
This syntax is available when you set the WeightsOutputPort property
to true.

Note:H specifies the System object™ on which
to run this step method.

The object performs an initialization the first time the step method
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 call the release method
to unlock the object.

Input Arguments

H

Beamformer object.

X

Input signal, specified as an M-by-N matrix.
If the sensor array contains subarrays, N is the
number of subarrays; otherwise, N is the number
of elements.

ANG

Beamforming directions, specified as a two-row matrix. Each
column has the form [AzimuthAngle; ElevationAngle], in degrees. Each
azimuth angle must be between –180 and 180 degrees, and each
elevation angle must be between –90 and 90 degrees.

Output Arguments

Y

Beamformed output. Y is an M-by-L matrix,
where M is the number of rows of X and L is
the number of beamforming directions.

W

Beamforming weights. W is an N-by-L matrix,
where L is the number of beamforming directions.
If the sensor array contains subarrays, N is the
number of subarrays; otherwise, N is the number
of elements.

Examples

Apply phase shift beamforming to the signal received by a 5-element
ULA. The beamforming direction is 45 degrees azimuth and 0 degrees
elevation.

% Simulate signal
t = (0:1000)';
x = sin(2*pi*0.01*t);
c = 3e8; Fc = 3e8;
incidentAngle = [45; 0];
ha = phased.ULA('NumElements',5);
x = collectPlaneWave(ha,x,incidentAngle,Fc,c);
noise = 0.1*(randn(size(x)) + 1j*randn(size(x)));
rx = x + noise;
% Beamforming
hbf = phased.PhaseShiftBeamformer('SensorArray',ha,...'OperatingFrequency',Fc,'PropagationSpeed',c,...'Direction',incidentAngle,'WeightsOutputPort',true);
[y,w] = step(hbf,rx);

Algorithms

The phase shift beamformer uses the conventional delay-and-sum
beamforming algorithm. The beamformer assumes the signal is narrowband,
so a phase shift can approximate the required delay. The beamformer
preserves the incoming signal power.