Questions tagged [beamforming]
Forming a beam (directional gain) and, sometimes, shifting the beam direction.
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42 views
How to generate a beam pattern from a beamformer on 3D
given a 3D microphone array with $M$ microphones, $d(f,\Theta)\in \mathbb{R}^{f\times M}$ is the steering vector for a given direction $\Theta=(\varphi,\theta)$, inclanation and azimuth respectively.
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17 views
Steering vector for beamforming in 3D
I am trying to implement a steering vector in 3D for beamforming. Let $A\in \mathbb{R}^{M\times 3}$ be a matrix containing the $(x,y,z)$ coordinates for $M$ sensors and the impinging source direction ...
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9 views
Question on unitary DFT matrix based beamforming
I am trying to experiment with digital beamforming for the first time & found a lot of literature making use of unitary DFT based beamforming but wasnt able to figure why(or how) DFT-based ...
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2answers
81 views
Proving that a product of matrices invertible
Given $R_x$ a Positive Definite (PD) covariance matrix of size $M\times M$ and $C$ a full rank $M \times N$ matrix, I want to prove that $C^* R_x^{-1} C$ is invertible to derive the Linearly ...
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25 views
Hot to generate image through Delay and Sum algorithm
I want to generate image through Delay and Sum algorithm. The list of the formula are attached, I have calculated rij(t) which is nothing but signals in time domain (1xn matrices), and the tij(x,y) (...
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3answers
79 views
Amplify Sound From Known Direction
I have microphone array which records sound. There is one main sound which direction I know and some noises in the background. Now I want to selectively amplify sound from known direction. This looks ...
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24 views
How to create test vectors for wideband beamforming aplications?
I'm trying to create test vectors for a beamforming algorithm I'm simulating in Matlab. I have a complex signal and I want to create the signal as seen by each antenna element. This will allow me to ...
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1answer
57 views
Implementing MVDR beamformer in the STFT domain
I am trying to implement an MVDR beamformer for the first time. I was reading a couple of papers and books with many different notations and I am a bit confused.
In my case, without loss of ...
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1answer
44 views
Beamforming but only for total power?
Is there a method to speed up beam-forming if you only care about the total power in a given direction, or total power in frequency groups? I've googled this, and can't find anything. My intuition ...
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1answer
39 views
frequency/phase offset estimation in satellite DOA beamforming applications
In satellite QPSK demodulation, we first estimate and remove the phase offset introduced by the channel. Then, we demodulate the baseband information bits (I & Q channels).
In satellite DOA ...
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65 views
Linear Combiner Based LMS Transfer Function
I am currently working on narrowband beamforming and looking to compute the transfer function for a linear combiner based LMS. While doing a quick search I have found the following article which ...
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2answers
197 views
Tetrahedral microphone array beamforming
I have a microphone array of 4 channels taken as channels [6,10,22,26] from Eigenmike spherical microphone array. I wish to do 3D beamforming and create $8\times 4$ beams, 4-elevations with 8 ...
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118 views
How to realistically represent antenna elements in phased array system alongside it's 3D gain response?
Please find the figure below where I've plotted a 3D gain response(in dB) of an antenna array system for beam-steering application and overlaid the actual antenna element(in red X marks surrounded by ...
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1answer
35 views
Beamforming back lobes question
When performing a conventional digital beamforming I see in some textbooks they show beam patterns as
where the arrival angle ranges between -90 to 90 degrees. But then other places show the full ...
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24 views
Can the j be equal to k in the first formula ?In MISO system
In this system model,the received signal available for RF EH at each RX_k is given by
However,its SINR formula is given by
We can find that author said the j can't be equal to k,but their range are ...
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1answer
34 views
How multi layer map to different beams in LTE Beamforming
I understand for SU-MIMO Beamforming single layer maps to all antennas with phase shift applied to create beam. Also I understand in this case all beams will be carrying same signal (say s1).
But in ...
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48 views
Radar - CFAR processing post Digital Beamforming - efficient alternative methods
A radar using a ULA with a large number of elements(for instance N=150 for 1[deg] beamwidth[1]) is being designed.
After the Range and Doppler processing, Digital Beamforing is being performed, ...
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45 views
Space-time filtering vs. beamforming
Say I have a dense linear array of sensors in space and an acoustic signal propagating through them.
In this case, how would delay-and-sum beamforming compare to space-time filtering by masking the ...
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1answer
67 views
Beamforming question
I'm working on a beamforming network. Every node in the network is half-duplex and has a linear antenna array that is capable of digital beamforming. A receiving node can be capable of forming any ...
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54 views
Multiple beam beamforming
For digital beamforming, we can form as many beams as we want. No matter where I read about this subject I cannot find any discussion of the interference that one would expect between beams (not ...
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2answers
256 views
how to calculate the maximum obtainable directivity for a microphone array?
Introduction
The relationship between the maximum obtainable directivity and aperture of an antenna is described by:
$$ D = \frac{4\pi A_e}{\lambda^2} $$
Where $D$ is the directivity, $A_e$ the ...
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0answers
285 views
Time-Delay beamforming delay computation
I'm trying to implement a beamforming algorithm in python and I'm stuck with the time-delay computation for a rectangular array.
I'm using the following equation to compute the delays based on the ...
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1answer
142 views
Calculation of Correlation Matrix
In the description of any Beamforming Technique for microphone array signal processing there is a usage of the co-relation matrix.
What is the use of calculating such a co-relation matrix in such ...
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2answers
490 views
what is an alpha filter?
Currently, I'm working on adaptive beamforming using LMS approach, so they change the value of the step factor adaptively in which one of the steps is to pass the weight vector through an alpha filter....
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104 views
Generalized Sidelobe Cancelling performance
I'm tinkering with different adaptive beam-forming algorithms for a research project in which I want to use a Uniform Rectangular microphones Array (URA) to isolate speech in a room.
I am determining ...
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1answer
96 views
What is the best way to show beamformer enhances signal of interest over interference
I need to study an array's performance in terms of interference.
I have already analyzed the array's white noise gain which is the ratio of output and input SNR of the beamformer i.e. $\rm{SNR_o} / {...
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2answers
758 views
Beam width of linear array using MVDR beamformer
I did delay and sum beamforming technique and MVDR beamforming technique in MATLAB in ...
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138 views
Superdirectivity Beamformer for Circular microphone array
The matrix below represents the inverse of correlation matrix assuming diffuse noise field. I am unable to figure out the values of the elements of this matrix.
how to calculate $c_{M}(\omega)$ ?
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1answer
106 views
Design of a filter with given bandwidth and sidelobe level using Parks–McClellan algorithm
I want to design a filter (beamformer) with a given bandwidth (beamwidth) and sidelobe level using Parks-McClellan algorithm. I use "firpm" function of MATLAB. however, I cannot reach a solution for ...
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1answer
1k views
Delay-and-sum beamforming: implementing steering in C
I am currently trying to understand how delay-and-sum beamforming works.
I have found this website which explains the process of this technique very well in which the following C code is provided:
<...
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1answer
303 views
How to compute beam pattern given a delay-and-sum filter in spectral domain?
Given a two-mic system (the mic spacing $d$ is known), how can I compute the beam pattern (see the Figure below) over frequency and angle $g(f,\theta)$ for a pair of spectral filters ($H_0$ for ...
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1answer
178 views
Relationship between matrix rank and beamforming
I always encounter the term matrix rank in papers related to beamforming. I am only familiar with the basics of beamforming (delay sum beamformer, basic capon). Can someone explain the significance of ...
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1answer
323 views
What is homogeneous noise field?
What is the formal definition of homogeneous noise field? Is there any example of it?
Thanks.
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1answer
184 views
Filter signal for beamforming and phase response
I was wondering this for quite some time but couldnt find a satisfied answer. Seems like not a lot worry about phase response in general. But maybe I'm thinking about it in a wrong way...
I want to ...
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1answer
228 views
Would a visible light beamforming “telescope” be feasible?
If you had a phased array of high speed photodiodes that were spaced sufficiently far apart, would it be possible to apply beamforming theory to create a steerable visible light "telescope"?
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2answers
208 views
MVDR Beamformer, minimize but do not change pattern in main beam
Is there a way to minimize all signals that are not coming from the mainbeam?
I would like to keep the main beam, or at least +-3° around the main peak stable.
When I estimate the covariance from ...
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1answer
838 views
Spatial sampling frequency equation
Upon reading this microphone array tutorial, I'm stuck in the following piece:
The spatial sampling frequency along the x-axis is given by
$f_{x_s} = \frac{\sin \theta \cos \phi}{\lambda}$
...
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1answer
952 views
Difference between Uniform Linear Array (ULA) 3 dB beamwidth and bearing resolution
Is there a difference between linear array 3dB beam width and linear array bearing resolution ?
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117 views
Beam pattern for a linear array comprised of rectangular transducers
I am looking for the beam pattern of a linear array with uniform spacing, $d$, between $n$ elements.
I know for an array comprised of circular pistons it can be derived from
$$\frac{1}{n}\frac{\sin[...
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1answer
646 views
DSP with 8+ inputs for simple beamforming
Does anyone know of a DSP that is cheap and has 8+ inputs (8 I2s mics) and that can perform beam forming calculations? I'm super new to circuit design so preferably one thats beginner friendly.
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1answer
140 views
Beam Former linear array antenna
How can I design a beam former (with weigth vector $w$) that protects a signal coming from an angle of arrival $\theta_0$ and completely suppresses signals coming from $\theta_1,\theta_2,...,\theta_k$?...
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1answer
813 views
Beamforming techniques - pros and cons
I would like some advice on which beamforming method to use from someone with experience in the field.
I have radar data from the ocean which has been transmitted by an omnidirectional transmitter ...
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1answer
2k views
Beamforming using MATLAB
I'm attempting to beamform some data which has signals coming from all directions in a 180 degree range.
I found an example of using the phased array toolbox, in MATLAB, to beamform a signal in https:...
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2answers
190 views
What does the $n$ do in $1/(j \omega)^n$
I'm currently working through a research paper on beam forming. In this paper a magnitude compensation is introduced to compensate for frequency dependency. Due to other calculations low frequencies ...
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1answer
222 views
Which parameters defines a polar plot?
I need to convert a polar plot into a short array of 3-5 values. This array should describe the polar plot as best as possible.
For example, I know that I can use the beamwidth which is also known as ...
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1answer
945 views
Delay and sum Beamforming
What is the difference between the weight vector (w) and the steering vector a(θ)?
I initially assumed they were the same thing, but the literature seems to be to be a bit fuzzy with this (or maybe ...
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1answer
315 views
Beam resolution improvement of linear array using MVDR beamformer
One of the major advantages of using MVDR beam former is to improve bearing resolution as compared to conventional delay & sum beam forming. The bearing resolution is defined by 3 dB beam width of ...
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1answer
220 views
Narrowband DOA Beamforming techniques on Wideband signal
I'm trying to implement a tracking system (undergrad thesis) using DOA of acoustic signals. I'm testing this by playing a 2kHz sound and receiving the signal with four microphones in a ULA.
So, the ...
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1answer
224 views
Direction of arrival and distance to source
Suppose we have $3$ receivers $a,b,c$ and one wave source which are all located on the same $XY$ plane and we do not know the position of only $c$ on the plane.
Assume a plane wave is transmitted $s(...
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Physical Interpretation of $\mathbf A$ beamforming Matrix
The directivity of an array is defined as:
$$ D = \frac{1}{2} \int_{-1}^{1} \lvert B_{u}(u)\rvert^{2} du$$
Where $B_{u}(\cdot) = \mathbf{w}^{H} \mathbf{v}(\cdot) $ is the beampattern of the array in ...
