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Questions tagged [multi-channel]

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17 views

What do you mean by radio sensing a channel?

I am slowly getting into the field of wireless communications, in particular with WiFi based communications. 802.11 MAC mentions that A station wishing to transmit first listens to the medium ...
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0answers
21 views

Two inputs channel capacity

Assume that we have an AWGN channel with two inputs (A,B) and the o/p is written as Y = A + g B + Z where Z is an independent Gaussian noise with zero mean and unit variance and g is a constant ...
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1answer
35 views

channel estimation for cdma

I am looking for a method to make a multi-user channel estimation with CDMA. Here is my question: Is there a way to estimate multi-user channels with their spreading codes? If yes, what is the ...
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1answer
66 views

What's the difference between SISO and SIMO in using matched Filters

Suppose we are transmitting a signal $x$ in $OFDM$ with $N$ subcarriers, After performing Parallel/Serial conversion and then N-points FFT, we suppose to have signal $s = IFFT^Hx$, Then adding the ...
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2answers
241 views

what does mean quasi-static channel [closed]

When I read papers about channels, I usually see something Quasi-static Channel, Does "Quasi-static Channel" mean "time-variant channel" or "time-invariant channel"?
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0answers
62 views

Common mode signal cancellation on multi-channel system

I have a system consisting of 32 horizontal plus 32 vertical charge sensitive wires. They are part of a particle detector and each one is coupled to a charge amplifier consisting of preamp stage ...
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1answer
59 views

concurrent multiple sound sources seperation for TDoA estimation

consider a room with some sound resources and several mics, these sound resources almost concurrently emit sound signals. As for one mic, it may pick up sound signals from different sound sources ...
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2answers
81 views

How to estimate ALL time-delays across MULTIPLE signals?

Imagine there are 100 recordings of the same signal or pattern, but those recordings are not properly aligned with each other in time. In other words, each sample has some unknown time delay in ...
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1answer
66 views

Eight Sub Band Filter Design

I have to process a RF signal band with bandwith between 75MHz and 100MHz to divide it in up to 8 contiguous subbands, each one with a bandwith programmable between 50kHz and 25MHz, in 25kHz steps. ...
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1answer
334 views

DoA estimation using microphone array

I am using an array of 4 microphones in a square formation. My goal is to estimate the direction (azimuth only) of incoming speech sound. The array looks like this: I have recordings from the array ...
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1answer
615 views

Subcarrier spacing in OFDM

The idea of OFDM is to spread data across multiple overlapping subcarriers. As they are orthogonal it is still possible to demodulate them. That means, all other subcarriers are 0 at the evaluation ...
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0answers
153 views

Distribution of the output of AWGN channel

$$\mathbf{Y}=\mathbf{X}+\mathbf{W}$$ $\mathbf{X}$ is input, an $n$-dimension equiprobable vector in a finite subset of complex space $\mathcal{A}^n \subset \mathbb{C}^n$ with norm $\sqrt{\rho n}$ (...
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1answer
379 views

PortAudio: how to generate multiple sounds

I have simple wave generator in PortAudio. I'm creating single sine wave, and then I use a lookup sine to play it. Now I've stucked here. I have no idea how I can add another sine sound. Is it ...
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1answer
344 views

What is the suitable mathematical form of the multipath channel impulse response?

I am trying to understand the nature of a wireless multipath channel impulse response but I am a bit confused while interpreting the time domain multipath impulse response. There are different ...
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0answers
41 views

Actual measurements of the influence of fading and multipath on HF radio communication

I'm looking for papers or books that contain actual measurements of the influence one has to expect in HF radio communication. I'm interested in this, because i've simulated the influence of a ...
4
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1answer
69 views

Advice needed for separating 3-channel signals

I'm working on a personal project, where I'm trying to make a touch screen that uses force sensors as the basis of the technology. The rig I've made has have three transducers underneath a square ...
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2answers
347 views

What is the relation between noise (AWGN) variance and number of antennas?

I'm working in two Matlab scripts trying to simulate a MIMO system using OFDM (downlink) and SC-FDE (uplink). My question is: for different numbers of transmit and receive antennas, what is the ...
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1answer
160 views

How to implement a $j$-level $M$-band wavelet transform of an image?

I want to implement an $M$-band (or multi-band) wavelet transform, to be used for feature extraction on images. Is there a built-in Matlab function available? Do I have to implement is using filter ...
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1answer
1k views

Real-time delay between signals

I currently have a real-time noise suppression algorithm based on two inputs from different microphones. It has passed most tests that I have thrown at it, however when the signal I am trying to ...
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0answers
39 views

Dividing a signal in channels

I have a signal in time domain, and I have to convert it into frequency domain and divide it into 100 channels, and find the center frequency of each channel. I am not good in "MATLAB" so how to do ...
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2answers
164 views

Changepoint Detection of a 2D signal

Consider the 2D signal below I would like to find the changepoints in the signal (using a hierarchical approach). Based on our visual observation, we can see there are 2 main changepoints where the ...
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0answers
28 views

Can someone help me with ETSI/BRAN Indoor wireless channel specification and implementation in MATLAB

I want to implement ETSI/BRAN Indoor Model A channel, i have the delays for the paths tau=[0 10 20 30 40 50 60 70 80 90 110 140 170 200 240 290 340 390]*10^(-9); and the Average Relative Power (dB) ...
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2answers
6k views

Hermitian symmetry in OFDM systems

I am trying to understand the usage of Hermitian symmetry in OFDM systems and have a couple of questions regarding this. What is the reason of using the Hermitian symmetry in OFDM? How can we arrange ...
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2answers
93 views

Finding the best principle component

The title might be unclear, but the problem is this. I have a signal sampled 1500 times with a rate of 60/s, and a sensor array 512 units large. There is a lot of noise, echo and other frequencies ...
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1answer
528 views

Can I compute signal-to-noise ratio on a vector-valued or multi-channel signal?

I have a dataset that contains multiple channels recorded over time (think EEG or EMG), and I'm working on a computational model for this data. When I have a working version of the model, I'd like to ...