Engee documentation

ULA MVDR Spectrum

Minimum Variation Distortionless Spatial Spectrum Analyser (MVDR) for ULA.

ula mvdr spectrum

Description

The unit ULA MVDR Spectrum estimates the spatial spectrum of incoming narrowband signals by scanning a wide-angle region usage of a narrowband minimum variance distortionless beamformer (MVDR) for a uniform linear array (ULA). The block additionally computes the direction of arrival (DOA) of a given number of signals by finding the peaks of the spectrum. This estimator is also referred to as the Capon estimator.

Ports

Input

Port 1 - received signal
`complex matrix

Input signal defined as a matrix, columns of which correspond to channels. The rows correspond to the signal samples.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool

Support for complex numbers: Yes

Output

Y - spatial spectrum
`non-negative real vector column

The spatial spectrum returned as a non-negative real vector-column. Each entry represents the magnitude of the estimated spatial spectrum. Each entry corresponds to an angle given by the Scan angles (deg) parameters.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool

Support for complex numbers: Yes

Ang - signal arrival directions
`non-negative real vector column

Signal arrival directions returned as a non-negative real vector-column. The angle of the direction of arrival is the angle between the direction to the source and the axis of the antenna array. The units of the angle are degrees. The length of the vector is equal to the number of signals specified by the Number of signals parameters. If the peaks in the spectrum cannot be detected, the result returns NaN.

Dependencies

To use this port, select the checkbox for the Enable DOA output parameters.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool

Parameters

Main

Signal propagation speed - speed of signal propagation, m/c
3e8 (by default) | positive scalar

Signal propagation speed as a real positive scalar. By default, the value of the speed of light is 3e8 m/c.

The unit of measurement is metres per second.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Operating frequency (Hz) - operating frequency of the system
3e8 (By default) | positive scalar

The operating frequency of the system specified as a positive scalar. The unit of measurement is hertz.

Data types: Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool

Number of bits in phase shifters - number of bits in phase shift quantisation
0 (by default) | non-negative integer

Number of bits used to quantise the phase shift component of the beamformer or control vector weights. Specify the number of bits as a non-negative integer. A value equal to zero means that quantisation is not performed.

Forward-backward averaging - enable forward-backward averaging
off (by default) | on

Select this checkbox to use forward-backward averaging to estimate the covariance matrix for antenna element arrays with conjugate-symmetric array manifold structure.

Enable DOA output - output arrival directions through the output port
enable (by default) | enabled

Select this check box to output the arrival directions of incoming signals (DOA) through the Ang output port.

Number of signals - the expected number of incoming signals
1 (By default) | positive integer

Specify the expected number of signals to estimate the directions of arrival of incoming signals (DOA) as a positive integer scalar number.

Dependencies

To use this parameter, select the Enable DOA output checkbox.

Sensor Array

Specify sensor array as - method of specifying an array
Array (no subarrays)

Method of specifying the array specified as Array (no subarrays).

  • Array (no subarrays) - block parameters are used to set the array.

Element

Element type - types of antenna array elements
Isotropic Antenna (by default) | Cardioid Antenna | Cosine Antenna | Custom Antenna | Gaussian Antenna | Sinc Antenna | Omni Microphone | Custom Microphone

Type of antenna array element.

Available values:

  • Isotropic Antenna.

  • Cardioid Antenna

  • `Cosine Antenna

  • `Custom Antenna

  • `Gaussian Antenna

  • `Sinc Antenna

  • `Omni Microphone

  • `Custom Microphone

Operating frequency range (Hz) - operating frequency range of the antenna array element
[0,1e20] (by default) | ` real vector-string 1 by 2`

The operating frequency range of the antenna array element as a 1-by-2 string-vector in the form of [LowerBound,UpperBound]. The element has no response outside this frequency range. Frequency measurement units are Hz.

Dependencies

To use this parameter, set the Element type parameters to Isotropic Antenna, Cosine Antenna or Omni Microphone.

Baffle the back of the element - consider radiation through the rear beam of the pattern to the rear hemisphere of the Isotropic Antenna element or Omni Microphone.
Off (By default) | `on

Set this flag to exclude radiation to the rear hemisphere. The response from the rear hemisphere at all azimuth angles outside the ±90° interval from the broadside are set to zero. The broadside direction is defined as an azimuth angle of 0° and a place angle of 0°.

Dependencies

To use this parameter, set the Element type parameters to Isotropic Antenna or Omni Microphone.

Null axis direction - the direction of the axis along the null radiation.
-x (By default) | +x | +y | -y | +z | -z.

Axis direction along the null radiation.

Dependencies

To use this parameter, set the Element type parameters to Cardioid Antenna.

Exponent of cosine pattern - exponent of exponent degree when specifying the shape of cosine pattern
[1.5, 1.5] (By default) | non-negative scalar | real matrix of non-negative values 1 by 2.

The exponent of the degree of the exponent of cosine model as a non-negative scalar or a 1-by-2 real matrix of non-negative values. If the Exponent of cosine pattern is a 1 by 2 vector, the first element is the exponent of the exponent degree in the azimuth direction and the second element is the exponent of the exponent degree in the angle-of-place direction. When this parameters is scalar, the cosines in the azimuth and elevation directions are raised to the same degree.

Dependencies

To use this parameter, set the Element type parameter to Cosine Antenna.

Operating frequency vector (Hz) - array of operating frequencies of the antenna array element
[0,1e20] (by default) | real string vector

The array of operating frequencies of the antenna array element as a string vector 1 on of increasing real values. The element has no response outside the frequency range given by the minimum and maximum elements of this vector. The units of frequency measurement are Hz.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna or Custom Microphone. To set the response at these frequencies, use the Frequency responses (dB) parameters.

Frequency responses (dB) - frequency responses of the antenna array element
[0,0] (by default)| real vector-string.

The frequency response of custom antenna array elements is determined by the Operating frequency vector (Hz) parameters. The dimensions of the Frequency responses (dB) vector must match the dimensions of the vector defined by the Operating frequency vector (Hz) parameters.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna or Custom Microphone.

Input Pattern Coordinate System - selects the coordinate system of the custom antenna pattern
az-el (by default) | phi-theta.

Selects the user antenna pattern coordinate system, either az-el or phi-theta is specified. When az-el is selected, the Azimuth angles (deg) and Elevations angles (deg) parameters are used to specify the coordinates of the directional pattern points. When the `phi-theta parameter is specified, the Phi angle (deg) and Theta angles (deg) parameters are used to specify the coordinates of the pattern points.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna.

Azimuth angles (deg) - azimuth angles of the antenna radiation pattern
[-180:180] (By default) | real vector-string

The azimuth angle values for which the antenna radiation pattern will be calculated as vector-string 1 at . must be greater than 2. The values of the azimuth angles must lie in the range from −180° to 180° inclusive and be in strictly ascending order.

Dependencies

To use this parameter, set the Element type parameter to Custom Antenna and the Input Pattern Coordinate System parameter to az-el.

Elevation angles (deg) - values of antenna pattern location angles
[-90:90] (by default) | real vector-string.

The values of the place angles at which you want to calculate the radiation pattern as vector 1 at . must be greater than 2. The units of measurement of the angles are degrees. The elevation angles must lie in the range from −90° up to and including 90° and be in strictly ascending order.

Dependencies

To use this parameter, set the Element type parameter to Custom Antenna and the Input Pattern Coordinate System parameter to az-el.

Phi Angles (deg) - values of Phi angles of the antenna pattern
[0:360] (by default) | ` real vector-line 1 on P`

Angular coordinates Phi of the points at which the antenna radiation pattern is specified. Defined as a real vector-string 1 on . must be greater than 2. The units of measurement of the angles are degrees. The values of the angles Phi must lie in the range from 0° to 360° and be arranged in strictly ascending order.

Dependencies

To use this parameter, set the Element type parameter to Custom Antenna and the Input Pattern Coordinate System parameter to phi-theta.

Theta Angles (deg) - values of Theta angles of the antenna radiation pattern
[0:180] (by default) | real vector-string 1 on Q

Theta angular coordinates of the points where the antenna radiation pattern is specified. Defined as a real vector-string 1 on . must be greater than 2. The units of measurement of the angles are degrees. Values of the angles Theta must lie in the range from 0° to 180° and be arranged in strictly ascending order.

Dependencies

To use this parameter, set the Element type parameter to Custom Antenna and the Input Pattern Coordinate System parameter to phi-theta.

Magnitude pattern (dB) is the magnitude of the antenna pattern
zeros(181,361) (by default) | real matrix Q on P | real array Q on P on L

Antenna pattern magnitude given as a matrix by or an array by by .

  • If the Input Pattern Coordinate System parameter is set to az-el, then is equal to the length of the vector defined by the Elevation angles (deg) parameter, in turn, is equal to the length of the vector defined by the Azimuth angles (deg) parameter.

  • If the Input Pattern Coordinate System parameter is set to phi-theta, then is equal to the length of the vector defined by the Theta Angles (deg) parameter, in turn, is equal to the length of the vector defined by the Phi Angles (deg) parameter.

The value of is equal to the value of the Operating frequency vector (Hz) parameters.

  • If the value of this parameter is a matrix to , then the same scheme is applied for all frequencies specified in the Operating frequency vector (Hz) parameter.

  • If the value is an array to to , each element to of the array specifies a pattern for the corresponding frequency specified in the Operating frequency vector (Hz) parameters.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna.

Phase pattern (deg) - the phase of the radiation pattern of the custom antenna
zeros(181,361) (By default) | real matrix Q on P | real array Q on P on L

The phase radiation pattern of the combined antenna, given as a matrix on or an array on on .

  • If the Input Pattern Coordinate System parameter is set to az-el, then is equal to the length of the vector defined by the Elevation angles (deg) parameter, in turn, is equal to the length of the vector defined by the Azimuth angles (deg) parameter.

  • If the Input Pattern Coordinate System parameter is set to phi-theta, then is equal to the length of the vector defined by the Theta Angles (deg) parameter, in turn, is equal to the length of the vector defined by the Phi Angles (deg) parameter.

The value of is equal to the value of the Operating frequency vector (Hz) parameters.

  • If the value of this parameter is a matrix to , then the same scheme is applied for all frequencies specified in the Operating frequency vector (Hz) parameter.

  • If the value is an array to to , each element to of the array specifies a pattern for the corresponding frequency specified in the Operating frequency vector (Hz) parameters.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna.

Align element normal with array normal - align the antenna array element normal with the array normal
On (By default) | Off.

If the parameters value is on, the pattern of the antenna element is rotated to align with the array normal. If off, the pattern of the element is not rotated.

If the antenna is used in an antenna array and the Input Pattern Coordinate System parameters is set to az-el, checking this checkbox rotates the pattern so that the x-axis of the element coordinate system points along the array normal. If no selection is made, the element pattern without rotation is used.

If the antenna is used in an antenna array and the Input Pattern Coordinate System parameters is set to phi-theta, checking this checkbox rotates the pattern so that the z-axis of the element coordinate system points along the array normal.

Use this parameter in conjunction with the Array Normal parameters of the URA and UCA arrays.

Dependencies

To use this parameter, set the Element type parameters to Custom Antenna.

Radiation pattern beamwidth (deg) - width of the antenna pattern beamwidth
[10, 10] (by default) | real scalar | real vector-string 1 by 2

Antenna pattern beamwidth in degrees.

Dependencies

To use this parameter, set the Element type parameters to Gaussian Antenna.

Polar pattern frequencies (Hz) - values of frequencies for polar pattern of the microphone
1e3 (By default) | real scalar | real vector-string 1 by L.

The frequency values for the polar radiation pattern are given as a real scalar or real vector-string 1 on . The frequencies lie within the frequency range specified by the parameter Operating frequency vector (Hz).

Dependencies

To use this parameter, set the Element type parameters to Custom Microphone.

Polar pattern angles (deg) - angle values for the polar pattern of the microphone
[-180:180] (by default) | real vector string 1 on P.

The angle values for the microphone’s polar pattern are specified as a vector . The angles are measured from the centre axis of the microphone and should range from −180° to 180° inclusive.

Dependencies

To use this parameter, set the Element type parameters to Custom Microphone.

Polar pattern (dB) - polar pattern of the microphone
zeros(1,361) (by default) | `real vector string 1 to L'.

Set the polar pattern magnitude of the user microphone element as a real vector-string 1 by , where is the number of frequencies specified in the Polar pattern frequencies (Hz) parameters. The string represents the polar pattern magnitude measured at the corresponding frequency specified in Polar pattern frequencies (Hz). The directional pattern is measured in the azimuth plane. In the azimuth plane, the angle of place is 0° and the centre axis is 0° in azimuth and 0° in elevation. The polar pattern is symmetrical around the centre axis. Based on the polar diagram, you can construct the microphone’s radiation pattern in three-dimensional space.

Dependencies

To use this parameter, set the Element type parameters to Custom Microphone.

Array

Number of elements - number of antenna array elements
2 for ULA arrays and 5 for UCA arrays (by default) | ` an integer greater than or equal to 2`.

The number of ULA antenna elements specified as an integer greater than or equal to 2.

Element spacing (m) - the distance between antenna elements in the array
` 0.5 for ULA arrays (by default)` | ` positive scalar for ULA arrays | ` two-element vector of positive values for URA arrays

Distance between neighbouring antenna elements:

  • ULA - specify the distance between two neighbouring antenna elements as a positive scalar.

  • URA - specify the distance as a positive scalar or vector of positive values 1 by 2. If Element spacing (m) is a scalar, the row and column spacing are equal. If Element spacing (m) is a vector, the vector is [SpacingBetweenArrayRows,SpacingBetweenArrayColumns].

Array axis - direction of the linear axis of ULA
y (by default) | x | z

ULA linear axis direction specified as y, x or z. All elements of the ULA antenna array are uniformly distributed along this axis in the local antenna coordinate system.

Taper - change of directional pattern of the antenna array elements
1 (by default) | complex scalar | complex vector

The change of the directivity diagram of the antenna array elements is specified as a complex scalar or complex vector 1 at , where is the number of antenna array elements.

The coefficients that change the directivity pattern, also called element weights, multiply the responses of the antenna array elements. The coefficients change both the amplitude and phase of the response to reduce side lobes or the direction of the main response axis.

If the value of the Taper parameters is a scalar, the same weight is applied to each element. If Taper is a vector, then the weight from the vector is applied to the corresponding antenna array element. The number of weights must correspond to the number of antenna array elements.