Questions tagged [beamforming]
Forming a beam (directional gain) and, sometimes, shifting the beam direction.
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19 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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39 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
136 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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23 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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19 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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18 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
16 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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26 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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30 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
43 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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28 views
Phase estimation in Beamforming
If I have a modulated signal $A\cos(2\pi f c t + \phi)$, I can demodulate it using IQ demodulator and estimate the phase using I and Q channel information. When it comes to MIMO case (specifically ...
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43 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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157 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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217 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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47 views
Spatial Correlation Matrix
I have been studying the Minimum Variance Distortionless Response beamformer, and I've come to find I don't understand the spatial correlation matrix as given.
For clarity, consider the output of a ...
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1answer
91 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
79 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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71 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
90 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
544 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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0answers
111 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
83 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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781 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
248 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
137 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
247 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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150 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
171 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
192 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
583 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
711 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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86 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
456 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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110 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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616 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
1k 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
189 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
177 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
782 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
290 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
203 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
187 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 ...
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840 views
Difference between single layer and dual layer beamforming in LTE
I'm trying to understand the difference between single and dual layer beamforming in LTE as described in TS 36.101 section B.4.1 and B.4.2 respectively. Also refer to TS 36.211 section 6.3.4.2.3 for ...
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1answer
983 views
Calculating covariance matrix for MVDR beamforming
I am trying to calculate the covariance matrix that is required for the calculation of an MVDR beamformer. I am getting confused as to how to calculate it. I have an array of 3 microphones each with a ...
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2answers
1k views
Intuitive interpretation of Fourier transform in beamforming
When applying Fourier transform in time domain the signal will be carried to frequency domain. And when we apply Fourier transform in spatial domain the signal will be carried to directivity domain.
...
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2answers
815 views
Can a narrowband beamformer be used for speech separation
In my master thesis I am trying to implement a beamformer.
I've already done the delay-sum part 1 year ago. I have been told:
in FIR filtering we can do
FFT --> null the unwanted frequency bin --> ...
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138 views
How to think about beamforming when there's no “space” between receivers?
I'm trying to wrap my head around how does "beamforming" work when there's no physical "space" between receivers.
My background knowledge:
I've always thought about beamforming as a sort of spacial ...
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68 views
The Rank Of Broadband LCMV Beamformer Constraint Matrix
So I am wondering why I keep seeing that the rank of the LCMV Broadband Constraint Matrix is equal to the number of constraints, when in practice, I find that the rank is only 1. This is precluding me ...
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2answers
240 views
IFFT of Microphone Array Directivity Response
I am implementing a microphone array simulation in my thesis.
My prof and many documents indicates that microphone array behaves like filters in DSP but instead time-frequency domain there exists ...
