System object: phased.SubbandPhaseShiftBeamformer
Package: phased
Beamforming using subband phase shifting
Y = step(H,X)
Y = step(H,X,ANG)
[Y,W] =
step(___)
[Y,FREQ]
= step(___)
[Y,W,FREQ]
= step(___)
Note:
Starting in R2016b, instead of using the 
performs
subband phase shift beamforming on the input, Y
= step(H
,X
)X
,
and returns the beamformed output in Y
.
uses Y
= step(H
,X
,ANG
)ANG
as
the beamforming direction. This syntax is available when you 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
.
[
returns the center frequencies
of subbands, Y
,FREQ
]
= step(___)FREQ
. This syntax is available when
you set the SubbandsOutputPort
property to true
.
[
returns beamforming weights and
center frequencies of subbands. This syntax is available when you
set the Y
,W
,FREQ
]
= step(___)WeightsOutputPort
property to true
and
set the SubbandsOutputPort
property to true
.
Note:
The object performs an initialization the first time the 

Beamformer object. 

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

Beamformed output. 

Beamforming weights. 

Center frequencies of subbands. 
Apply subband phase shift beamformer to an 11element ULA. The incident angle of the signal is 10 degrees in azimuth and 30 degrees in elevation.
% Signal simulation ha = phased.ULA('NumElements',11,'ElementSpacing',0.3); ha.Element.FrequencyRange = [20 20000]; fs = 1e3; carrierFreq = 2e3; t = (0:1/fs:2)'; x = chirp(t,0,2,fs); c = 1500; % Wave propagation speed (m/s) hc = phased.WidebandCollector('Sensor',ha,... 'PropagationSpeed',c,'SampleRate',fs,... 'ModulatedInput',true,'CarrierFrequency',carrierFreq); incidentAngle = [10; 30]; x = step(hc,x,incidentAngle); noise = 0.3*(randn(size(x)) + 1j*randn(size(x))); rx = x+noise; % Beamforming hbf = phased.SubbandPhaseShiftBeamformer('SensorArray',ha,... 'Direction',incidentAngle,... 'OperatingFrequency',carrierFreq,'PropagationSpeed',c,... 'SampleRate',fs,'SubbandsOutputPort',true,... 'WeightsOutputPort',true); [y,w,subbandfreq] = step(hbf,rx);
The subband phase shift beamformer separates the signal into several subbands and applies narrowband phase shift beamforming to the signal in each subband. The beamformed signals in all the subbands are regrouped to form the output signal.
For further details, see [1].
[1] Van Trees, H. Optimum Array Processing. New York: WileyInterscience, 2002.