phased.TimeDelayLCMVBeamformer
Time delay LCMV beamformer
Description
The TimeDelayLCMVBeamformer
object implements
a timedelay linear constraint minimum variance beamformer.
To compute the beamformed signal:
Define and set up your timedelay LCMV beamformer. See Construction.
Call
step
to perform the beamforming operation according to the properties ofphased.TimeDelayLCMVBeamformer
. The behavior ofstep
is specific to each object in the toolbox.
Note
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.
Construction
H = phased.TimeDelayLCMVBeamformer
creates
a timedelay linear constraint minimum variance (LCMV) beamformer System object, H
.
The object performs time delay LCMV beamforming on the received signal.
H = phased.TimeDelayLCMVBeamformer(
creates
a timedelay LCMV beamformer object, Name
,Value
)H
, with
each specified property Name set to the specified Value. You can specify
additional namevalue pair arguments in any order as (Name1
,Value1
,...,NameN
,ValueN
).
Properties

Handle to sensor array Specify the sensor array as a handle. The sensor array must
be an array object in the Default:  

Signal propagation speed Specify the propagation speed of the signal, in meters per second, as a positive scalar. You can specify this property as single or double precision. Default: Speed of light  

Signal sampling rate Specify the signal sampling rate (in hertz) as a positive scalar. This property can be specified as single or double precision. Default:  

FIR filter length Specify the length of the FIR filter behind each sensor element in the array as a positive integer. This property can be specified as single or double precision. Default:  

Constraint matrix Specify the constraint matrix used for timedelay LCMV beamformer as an
MbyK matrix. Each column of the
matrix is a constraint and M is the number of degrees of
freedom of the beamformer. For a timedelay LCMV beamformer, the number of
degrees of freedom is the product of the number of elements of the array and
the filter length specified by the value of the
Default:  

Desired response vector Specify the desired response used for timedelay LCMV beamformer as a column vector of length
K, where K is the number of
constraints in the Default:  

Diagonal loading factor Specify the diagonal loading factor as a positive scalar. Diagonal loading is a technique used to achieve robust beamforming performance, especially when the sample support is small. This property is tunable. This property can be specified as single or double precision. Default:  

Add input to specify training data To specify additional training data, set this property to Default:  

Source of beamforming direction Specify whether the beamforming direction comes from the
Default:  

Beamforming direction Specify the beamforming direction of the beamformer as a column vector of length 2. The
direction is specified in the format of Default:  

Output beamforming weights To obtain the weights used in the beamformer, set this property
to Default: 
Methods
step  Perform timedelay LCMV beamforming 
Common to All System Objects  

release  Allow System object property value changes 
Examples
Algorithms
References
[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.
Extended Capabilities
Version History
Introduced in R2011a