Questions tagged [beamforming]
Forming a beam (directional gain) and, sometimes, shifting the beam direction.
96
questions
2
votes
0
answers
28
views
Expanding cross correlation DOA estimation to n microphones
I need to detect the Direction of Arrival of a speech signal using an 8 microphone array as part of a project I've been working on. Currently, I have a working solution in the 2 microphone case:
$$G(\...
- 21
3
votes
1
answer
164
views
What's the point of differential beamforming?
I recently got into differential beamforming, in particular into the work of Benesty and Cohen. It seems to me that differential beamforming is something that just "takes place" when ...
- 98
2
votes
0
answers
61
views
optimal RX beamforming
I was asked this question in an interview couple of weeks ago. I think I answered it correctly, but I think I might missing some points. Here is the problem, following by my answer.
Part 1)
In Figure ...
- 77
5
votes
1
answer
189
views
Is there an intuitive explanation for how adaptive beamformers work?
Recently I've been learning about and implementing some adaptive beamforming schemes (particularly the SMI/Capon beamformer, and the Robust Capon Beamformer). I understand the mathematical derivations ...
- 195
0
votes
0
answers
17
views
Does generalized sidelobe canceller (GSC) differs for non-uniform array?
As I understand Linear Constraint minimum variance (LCMV) beamforming weights can be expressed as a solution of a convex optimization problem.In this case we have cost a function to optimize and there ...
- 131
1
vote
0
answers
44
views
PDM microphones to Matlab
As a beginner in DSP, I would appreciate your advice and recommendations on building a PCB with eight PDM microphones arranged in a circular distribution. My objective is to connect the PCB to a ...
- 111
3
votes
1
answer
549
views
Plotting beam pattern of uniform linear array
I am trying to reproduce Fig. 2.17 from the book 'Optimum Array Processing' by Van Trees.
The figure is a polar plot of the beam pattern $B_{\theta}(\theta)$ given by
$$B_{\theta}(\theta) = \frac{1}{...
- 359
2
votes
1
answer
56
views
Is it possible to generate SAR like pictures with a non moving MIMO radar and static scene?
Recently I study radar alot and was wondering if there is a possibility to generate SAR like pictures with MIMO radar.
Under the condition that the MIMO radar is not moving and the scene does not ...
- 21
1
vote
1
answer
594
views
Is the beamforming result described by this matlab code useful?
A narrow-band beamformer for $0$ degree in the frequency domain is created for $8$ sensors and compared with a usual delay and sum beamformer. The question can also be expressed as : can we have ...
- 29
1
vote
2
answers
111
views
Inverting $6 \times 6$ complex matrix on the ARM Cortex M4F processor
I want to invert a $6 \times 6$ complex matrix on the ARM Cortex M4F processor. I have the C code to invert a real matrix using the CMSIS library. Has anyone written a similar C code for complex ...
7
votes
2
answers
378
views
Why is the null of an adaptive beamformer narrower than antenna beam-width?
Question for those familiar with adaptive beamforming: Why is the null formed by an adaptive beamformer much narrower than the beamwidth of the antenna array?
Concrete Example
Suppose we have a simple ...
- 1,664
2
votes
1
answer
79
views
Basis Pursuit Denoising (BPDN) algorithm for Direction of Arrival Estimation
I am working on Compressive sensing algorithms for DOA estimation. Can i get any references for writing BPDN code in MATLAB.
9
votes
1
answer
301
views
What is the relationship between beamforming and Independent Component Analysis (ICA)?
My first inclination when thinking about the Cocktail Party Problem would be to use adaptive beamforming to isolate different signals, but this does not seem to be how the problem is commonly thought ...
- 1,664
1
vote
1
answer
92
views
Is there a way to get the "mode" of several recordings? (to remove 1-off noise)
I've got several (4) not-great audio recordings of the same short (a few minutes long) performance, each taken from different microphones. I'd like one high-quality clip of the event. This is... ...
- 131
1
vote
0
answers
75
views
Comparing directivity patterns of an un-tapered and tapered uniform linear array
Assume we have a uniform linear array (ULA) with N elements. We wish to compare the performance of a tapered (let us presume Taylor 4-bar, -30dB side-lobe) array to an un-tapered array. Let the ...
3
votes
0
answers
75
views
Why is optimal beam-forming vector w orthogonal to channel signature?
I am looking at an online document on optimal beam-forming methods: https://www.comm.utoronto.ca/~rsadve/Notes/BeamForming.pdf (sorry I could not find author info from the pdf).
One of the strategies ...
- 33
4
votes
1
answer
401
views
Using Least Mean Square (LMS) Filter for Beamforming on Linear Array in Julia
I have been trying to implement a simple LMS adaptive beamforming code. Since I don't have a MATALB license, I decided to use Julia since they are quite similar. In order to get a basic code working I ...
1
vote
1
answer
34
views
How to differentiate two different signals from their combined signal
I am having two omnidirectional microphones connected in endfire configuration. I am playing a male speech from 0 degree (front direction) of the endfire microphone configuration and female speech ...
- 293
1
vote
0
answers
157
views
Is there a good beginner's book for array microphone beamforming?
I have been working in the acoustics field for a while, and recently I got myself into Matlab and Python for signal analysis and some signal processing.
After making some test and analysis tools with ...
- 11
-1
votes
2
answers
56
views
Can beamforming be created by transmitting same signal with different phase
As known, the basic idea of beamforming is to transmit the same signal using more transmit antennas, let's say we have $4$ transmit; leading to increase the power of the transmitted signal as well as ...
- 640
1
vote
1
answer
89
views
what is the correct order of applying a nonlinear operation and downsampling (with anti-aliasing)
In UltraSound imaging, after beam-forming and obtaining the envelope, Log-compression which is a non-linear operation and scan conversion which is a 2D interpolation (with inherent down-sampling) is ...
- 1,328
0
votes
1
answer
166
views
sound source localization - calculation of sound intensity vector angles
I'm working on an acoustic source separation problem where I want to separate the voices of a choir based on intensity vector statistics.
I'm currently implementing a paper by Günel called “Acoustic ...
- 1
1
vote
1
answer
69
views
Does same data inserted to all antenna at beamforming?
I wonder do I understand beamforming right.
Question 1
Does same data inserted to all antenna at beamforming? Like figure below? The only different is through different phase shift? If it is right how ...
- 11
0
votes
0
answers
68
views
Forming the estimation manifold for a 2-D beamformer
Given an array of L sensors in a uniform planar array, with known positions in space, I would like to estimate both the angles of arrival and delays from a point source under multipath conditions ...
- 143
5
votes
3
answers
222
views
How to derive the "well-known" solution to Unconstrained Array Gain?
Can someone point me to a webpage or other resource that shows how to analytically solve the beamformer Unconstrained Array Gain expression in Henry Cox's 1987 IEEE paper "Robust Adaptive ...
- 111
0
votes
1
answer
147
views
Why is beamforming needed in 5G?
With the advent of 5G Era, base station density
increases, the cell radius decreases, and LOS propagation
gets more dominant. So, why do we need for beamforming in 5G NR, although we have smaller ...
- 3
1
vote
1
answer
202
views
Radar type application for narrow band only?
Not sure if this is the proper forum to ask this question, but still I am trying my luck.
I am looking for an application (in any area, medical, defence, or any other area) if exist, such that we want ...
- 131
0
votes
2
answers
149
views
Multi-input Single-output communication system
In case of communication in MISO system, if we have a system of 4 x 1, which means 4 transmitter with 1 receiver. Will the received signal be a vector of dimension 4 x 1 ? Or it will be 1 x 1 since ...
- 639
0
votes
1
answer
411
views
What is the driving Voltage?
While I was looking into ultrasonic transducer in order to transmit and receive a beam, I came across specification of a transducer stating driving voltage as 20Vrms. I am not sure what actually does ...
0
votes
1
answer
84
views
Is there a term called "Fourier Beamforming"?
I understand delay and sum beamforming, where we want to add the signals obtained from different sensors. But adding different time samples from different element of the array depending on the angle ...
- 131
1
vote
0
answers
68
views
Sign of manifold vectors in monostatic phased-array radar
I am reading some notes where the impulse response of phased-array to is given by;
$$
\beta S(\theta, \phi) \bar{S}^H(\theta, \phi) \cdot \delta(t-\tau)
$$
where
\begin{align}
\bar{S}(\theta, \phi)...
- 11
8
votes
1
answer
282
views
Beamformer implementation methods
I'm currently reading articles about the different type of beamformers. This spatial filtering is gonna be used for acoustic purposes, to focus the beam on the person we need to hear talking in a ...
- 81
0
votes
1
answer
255
views
Digital beamforming and phase shift stage insertion
I have read some literatures about the different topologies of beamforming and it came to my mind a question : where is applied the phase shift for each channel depending on the type of topology/...
- 21
0
votes
0
answers
108
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.
...
- 672
3
votes
2
answers
100
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 ...
- 198
3
votes
3
answers
205
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 ...
- 229
2
votes
1
answer
730
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 ...
- 672
1
vote
1
answer
100
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 ...
- 111
-1
votes
1
answer
89
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 ...
- 131
3
votes
2
answers
541
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 ...
- 672
3
votes
1
answer
100
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 ...
- 3,012
0
votes
0
answers
32
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 ...
- 159
0
votes
2
answers
185
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 ...
- 1
0
votes
1
answer
155
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 ...
- 3,012
1
vote
2
answers
756
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 ...
- 137
1
vote
0
answers
587
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 ...
- 684
-1
votes
1
answer
243
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 ...
1
vote
2
answers
5k
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....
0
votes
0
answers
183
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 ...
- 684
1
vote
1
answer
114
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} / {...
- 159