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# Questions tagged [matched-filter]

Matched filter is obtained by correlating a known signal, or template, with an unknown signal to detect the presence of the template in the unknown signal.

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### Comparison of matched filter methods

I recently asked a question about the identity $\mathscr{F}\big\{x^\ast(-t)\big\}=\mathscr{F}\big\{x(t)\big\}^\ast$. Based on the feedback I got, I tested out the dicrete version of this identity in ...
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### Which roll-off factor for root raised cosine to match rectangular filter as closely as possible?

I'm trying to match a signal with a rectangular pulse shape using a rrc filter. Which alpha (0.25, 0.5 or 0.75) is best for doing this and why? My gut says 0.25 but I really don't understand. Edit: ...
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### Does matched filtering with real samples have a 3dB gain over complex samples?

I am getting a shocking result from my matched filtering simulations and math. It would seem unlikely, but I'm seeing a 3dB gain in SNR if I process real samples instead of complex. Where is the ...
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### Matched-Filter Simulation [duplicate]

I need to simulate the paper (https://ieeexplore.ieee.org/abstract/document/1095790)which is about Matched Filters in MATLAB. I read the paper but still, I didn't understand it completely. Is there ...
161 views

### Matched filter, convolution with signals of various patterns. Explanation of results

I am trying to use matched filters for signal detection and advanced processing - to get additional information from the signal after the convolution with various templates. The task I have is pretty ...
1 vote
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### Understanding Matched Filter, delay

I am trying to build a filter for the detection of signals with the known form in noisy and low-amplitude data. I used a simple example in Python provided here: https://www.youtube.com/watch?v=...
54 views

### How do I match a filter to an AWGN channel?

I have the task to find a transition that fulfills the first Nyquist Criterion. After that I am supposed to match that filter to an AWGN channel. For the first part I thought a raised cosine ...
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### How does matched filter output provide sufficient statistic when the channel has ISI + AWGN?

In Forney’s MLSE paper (link: https://ieeexplore.ieee.org/document/1054829), Forney mentioned that the matched filter output is still sufficient statistics even with ISI (second column on page 365). I ...
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### Deconvolving while suppressing other known signals

Given a known impulse response $h(t)$ and an observed signal $y(t)=(h*x)(t)+n(t)$, my aim is to recover an estimate of $x(t)$ in the presence of unknown additive noise $n(t)$. If the mean power ...
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### Biphase/Manchester floating-point decoder based on matched filter

I need to perform soft Viterbi decoding on a Manchester-encoded BPSK/QPSK signals. To that end, I need a floating point Manchester decoder. Most of the implementations I have seen operate on hard bits....
1 vote
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### How to synthesise an approximate 'pulse' waveform from an observed section of a similar waveform

Following on from my previous question, kindly answered by @peter-k, I have a related one... I have, in a small interval $a \leq x \leq b$, a function $q(x) := q(x;\rho,\gamma)$ whose exact form is ...
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### How best to detect an unknown number of pulses of an approximate known form over an interval?

It is approximately 30 years since I last studied signal processing, but have lately encountered a problem for which I am confident the solution is well-known in the signal-processing world. I hope ...
1 vote
142 views

### Power of noise signal through a matched filter (Digital Receiver)

I am studying matched filters and the sense of signal to noise ratio. In a question I was given, stated that: Show that a matched filter of a signal $s(t)$ maximizes the SNR of the output on a ...
116 views

### Can I still use match filter (eg.RCC)at rx when there is none at tx? Can it help with ISI?

As the transmitter is restricted to size and power considerations, there is no way to apply a SRRC filter at tx side. Can I just put a RC(raised cosine filter) at the rx side to alleviate ISI?
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### Matching Filter & Raised Cosine Confusion

I'm reading from Communication Systems, 5th Edition by Simon Haykin. At some point we derived that Which is how the effect due to AWGN is minimized. Meanwhile, to minimize ISI we need $P(f)$ to be ...
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### Simulating Es/N0 by adding noise to analog signal

I believe I am familiar with simulating $E_s/N_0$ by adding noise to the output of the matched filter, but what would be the correct way to simulate $E_s/N_0$ starting with the analog signal at the ...
248 views

### Object Detection using audible sonar

I am currently working on a project of identifying the position and angle of the objects in an environment using sonar (audible) about 1 to 2 m away from a desktop speaker within an angular sector of ...
131 views

### I/Q samples treatment with Matlab

I collected Iridium (satcom) I/Q samples (5120 x 100000 complex double) and I would like to plot the range-Doppler response map by using the matlab tool (https://www.mathworks.com/help/phased/ref/...
151 views

### derivative matched filter

I am reading a reseach paper "Joint Synchronization of Carrier Frequency, Symbol Timing and Sampling Rate in Digital Satellite Receivers" written by Suesser-Rechberger B and Gappmair W and ...
225 views

### Matched Filter Confusion

I have seen some youtube explanations where matched filtering is explained as taking the input signal time reverse version with delay and then we do convolution of the input with this filter. But in ... 1 vote
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### signals and systems,matched filter concept

The system with impulse response hi(t) is known as the matched filter for the signal Xi(t) because the impulse response is tuned to xi(t) in order to produce the maximum output signal. My intuition ...
1 vote
201 views

### Pulse shaping with root-raised cosine filter for a non-Gaussian channel

I am here to check whether my line of thinking is correct. Root-raised cosine (RRC) filtering is one way to minimize intersymbol interference (ISI). Hence, we apply matched RRC filters on both sides ...
1 vote
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### Question about relationship between aliasing and matched filter

while I was reading J. Barry's textbook (https://www.springer.com/gp/book/9780792375487), page 308 says the following: "... symbol-rate sampling at the matched filter output is generally at less ...
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### Determine g(t) for minimal symbol error probability, given h(t), K=1 and Minimum distance receiver

Determine $g(t)$ for minimal symbol error probability, given $h(t)$, $K=1$ and Minimum distance receiver. $h(t)= \begin{cases} 0, & \text{$t<0$}\\ 2, & \text{$t\in(0\;, 10^{-3}...
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### Blind TDOA Estimation

I am not EE or DSP engineer, however I am working on a project that uses TDOA estimation for location finding. I am able to get the localization algorithm working using cross correlation to estimate ...
150 views

### Detection of a Pulse pattern with Matched filter

I am working on a hobby transmitter-receiver project. Presence of 4 pulses in T seconds is regarded as 1(not any number of pulses, should match below): lack of pulses during that T seconds is ...
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### What does the visual representation of matched filtering of images look like?

So I am using the Source Extractor to find point sources in my images and it offers the possibility to use matched filtering to enhance the detection results. In the documentation they also claim that ...
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### What is the best to confirm that the output of a matched filter for a linear FM chirp is correct?

I have written a matched filter in matlab to compress a linear FM chirp signal and would like to confirm that the results of my range compression. My question is what is the best way to do this? I ...
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### How do you perform range compression of SAR data on a 2D matrix?

I am building a Matlab program to process RADARSAT-1 data that came with this book. The book describes the steps to creating SAR image as follows I am currently implement the range compression step. ...
1 vote
203 views

### SVD vs matched filter

Reading about singular value decomposition (SVD) in the context of signal processing applications, one can separate the signal from the noise into orthogonal subspaces. On the surface this sounds like ...
1 vote
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### Matched filter - do I need to know the signal I am trying to find?

I need to identify a matched filter, and so have gone through the mathematics to do this as listed here https://en.wikipedia.org/wiki/Matched_filter which derives the optimal filter $h$ to apply to a ...
1 vote
178 views

### How to detect a signal while ignoring another signal which is a phase shifted version?

I have a signal coming from a sensor as shown below. This signal has high frequency noise (as can be seen from small fast wiggles) and four regions of interest where distinct spikes can be seen. The ...
325 views

### phase offset extraction using matched filter

I'm looking for an application of detecting the drift of a received signal carrier frequency from ADC clock of the receiver (in case of no drift, ADC clock should be optimally an integer multiple of ...
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### Optimal pulse shape for minimal interference in adjacent frequencies

I need to find an optimal pulse shape, that convoluted with matched filter on adjacent frequency will give minimal convolution/correlation (Minimal interference) for a given pulse length. For ...
1 vote
430 views

### Whitening Matched Filters for Equalizer

I was looking at the answer Whitened Matched Filter. It mentions that in case of ISI channel, we can use $g^∗(−t)$ as matched filter. For ISI channel, $r(t)=c(t)∗s(t)+n(t)$ where $r(t)$ is the ...
282 views

Coherent demodulation\detection is usually done via matched filtering in RF signal processing. In radar signals, coherent integration can be done if the phases of the returns are known. In terms of ...
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### SINR is 3-tap zero forcing filter

I have a following toy example: received signal: $y[n] = x[n] - x[n-1] + z[n]$ and with $\text{Pr}(x[n]=1)=0.3=\text{Pr}(x[n]=-1)$ and $\text{Pr}(x[n]=0)=0.4$ and $z[n]$ is a Gaussian distribution. I ...
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### How to understand MIMO zero forcing as a bank of decorrelators?

I am studying the zero forcing as a simple linear receiver for MIMO detection. according to these notes. The zero forcing can be understood as the following two ways. For a single stream $\mathbf{q}$,...
1 vote
705 views

### Synthetic Aperture Radar (SAR). How to do Range Compression?

I am trying to perform range compression to a raw SAR image [fast times, sensor position], Dr in code. I have the transmitted signal (chirp), g in code, and literature says range compression is ...
199 views

### where is the matched filter being used exactly in Rx PHY?

Recently I learned about the matched filter and its usefulness as it maximizes SNR at time t0. So I looked up online to see how this amazing filter is being used exactly in 802.11a Rx PHY, but couldn'...
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### Is maximizing hamming distance the same as minimizing correlation?

For the design of an error correcting code, I might wish to maximize the distance between the codewords $\sum a_i \oplus b_i$. For spreading sequences I'd like to minimize the cross-correlation at \$t=...
1 vote
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### Matched Filters for attenuation detection?

I have been reading about matched filters and I'm interested in possible uses for them, I have seen they are used very often in radar, in such a way that you send out a signal, and then you read the ...
1 vote
408 views

### Compensate delay of non-symmetric (non-linear phase) filter

Lets assume I want to apply a matched filter h which is non-symmetric to my signal x and the output is ...
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### Practical question about DFT in Matlab

Please consider this piece of code: ...
1k views

### What is matched filter in QPSK signal?

Consider we have received a QPSK signal. We than make I (In phase) and Q (quadrature component) which I understand is nothing but multiplying the received signal by the cos(2*pi*f) and -sin(2*pi*f) ...
1 vote
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### Is there a hypothetical situation where once can use Wiener filter prior Matched filter to get better result?

Is there a hypothetical situation where once can use Wiener filter prior Matched filter to get better result? Mostly I am looking for an example or a situation where both the filters are required as ...
1k views

### About understanding a Matched Filter

I have some basic doubt in understanding a matched filter (MF). Please note that I have already seen very informative post in this context Understanding the Matched Filter In what follows, I list ...
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### Designing Matched Filters on Arduino

I'm trying to develop a prototype at the moment that includes a sensor to detect how fast someone is typing on a keyboard. Essentially this sensor is a microphone that will be able to detect keyboard ...