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24 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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0answers
15 views

1D Microphone Array Performance in radius domain

In angle of arrival Microphone array's gain is good enough . But I am curious about microphone array's gain in the radius direction. I know microphone arrays can focus in to radius direction like ...
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0answers
19 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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1answer
41 views

IFFT of Microphone Array Directivity Responce

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 ...
4
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1answer
69 views

Calculating Beam pattern, Directivity of microphone array

As answered in Relationship of Fourier Transform and Spatial Directivity Pattern the relation between directivity pattern and weights is give. But I am bit confused, I have Beamformer weights ...
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0answers
31 views

Mean of the product of a signal with its conjugate

I have to find $E\{s_m\cdot s_n^*\}$, where $E$ denotes mean or expected value; $s$ is a signal at $m \in [1\ldots M]$ elements and $^*$ denotes its conjugate. I am doing it by dividing it into two ...
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1answer
111 views

Plotting antenna pattern in MATLAB

I have a beamformed output, say y = weights * signal, where the signal is gaussian,i.e signal = randn( 1 , 1e5 ). Now I want ...
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0answers
20 views

Understanting reference signal on Beamforming

Algorithms such as Minimum Mean Square error and Least Mean-Square use a reference signal. The weigth vectors are defined by minimizing the error between the array output and the reference. I don't ...
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1answer
32 views

Beamforming with directional sensors

Having photo-diodes with a very narrow field of view (+-10 degrees for half power) what should I consider when designing a beam-forming algorithm? I know that I could use many photo-diodes mounted in ...
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82 views

Which algorithms one can use for matrix inversion (for beamforming application MVDR/LCMV) in Fixed Point?

I have implemented beamformer(MVDR/LCMV) for speech enhancement in matlab, now I am trying to convert it to fixed point implementation. during the weight calculation step correlation matrix inversion ...
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17 views

Dolph-Chebychev window and Beam Steering

We have made a Doppler sonar which is comprised of a braodband transmitter and an 8-element receiver arranged linearly. We collected some data at 500 kHz. I would like to steer the beams and apply a ...
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2answers
110 views

Relationship of Fourier Transform and Spatial Directivity Pattern

I am reading over and over the Section 1.2 of most understandable mic array tutorial for me . A sound wave is dependent on time and space which can be observed in the great link. But I can't ...
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1answer
176 views

Directivity Pattern of microphone array

Directivity pattern of a microphone array is fourier transfrom of microphone weight values. By modifying the amplitude weights, we can modify the shape of the directivity pattern. I can really see ...
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1answer
63 views

Microphone Array null steering unexpected results after IFFT

I am writing an open source microphone array simulation program:SharpEar. When I give uniform weight to microphone array elements, the result in the angle is a sinc function as expected. There are 41 ...
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1answer
59 views

Auto/cross correlation of a cosine in the context of an adaptive beamformer

I am currently reading chapter 13 of 'Adaptive Signal Processing' by Widrow and Stearns, so if anyone happens to have a copy of the book to hand it could be helpful. I am reading the chapter on ...
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1answer
113 views

use of complex conjugate of weight vectors in beamforming literature

in beamforming literature, people generally quote the following as a starting point: $y(k) = \sum_{i} w_i^*\cdot x_i(k)$ Here: i varies from 1 to N where N is the number of sensors $w_i^*$ is the ...
4
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1answer
163 views

Is it possible to do further beamforming on already beamformed data?

I've a circular array of eight FM antennas. I'm doing digital beamforming to form eight beams with the following beam patterns: The objective is to reduce my side lobes even further, and to get ...
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2answers
226 views

practical wideband digital beamforming for large arrays in radar applications

I do understand the mathematics behind digital beamforming but I am not sure how such systems are practically implemented. For example, in a typical wideband FMCW radar operating in S-band, the ...
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0answers
142 views

Question on spatial sampling for non-linear and/or non-uniform arrays

I am a little confused as to how to compute the nyquist criterion for a sensor array that is not linear, and/or non-uniform. For the linear, uniformly spaced case, the spatial nyquist is delimited by ...
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1answer
835 views

Difference between 'conventional' and 'adaptive' beamformers?

This might be a terminology question but I am not sure. Basically, what is the difference between conventional beamformers, and adaptive beamformers? I thought that all beamformers were inherently ...