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1500 questions
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Estimate the Filter Coefficients of 1D Filtration (Convolution)

I have an output signal $y$ which is an input signal $x$ convolved $\star$ with an impulse response function $h$ with some added noise $n$ : $$y(t) = h(t) \star x(t) + n(t)$$ I know the input signal $x$ and output signal $y$ and would like to…
Leo
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How do I apply a Chebishev filter?

I read a paper about a brain-computer interface. In this paper the authors reported "each signal has been filtered with an 8-order band-pass Chebishev Type I filter which cut-off frequencies are 0.1 and 10 Hz and has been decimated according to the…
alfa
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Designing a lowpass filter to minimize aliasing in pre-decimated streaming audio

I need to apply low-pass filter to PCM files. There are several methods such as FIR filters, IIR (butterworth-chebyshev..) filters but it seems to me applying Fast Fourier transform and eliminating higher frequencies is the closest way to an ideal…
Mete
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FIR vs IIR filter

In my filter design, FIR gives order 14 and IIR gives order 8 or 4. so what are the disadvantages of IIR design?
Jayesh Parmar
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4 answers

Does instability make an otherwise LTI system nonlinear (or time-variant)?

I am spinning this question off from the question from johnny. Matt L. and I have had directly opposite conclusions to johnny's question. I want to decouple the question from issues of causality and other goofy stuff. So we have a simple…
robert bristow-johnson
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How do Phons relate to loudness?

Let's say I have the very same signal stored in 2 .wav files. And lets say I process each file using a function, and it is established that one file is 20 phons larger than the other. Lets ignore how that function calculates this. Does this mean…
Baz
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How to classify accelerometer data?

I am trying to detect if a car did accelerate or did brake by using the accelerometer of the iPhone. In the figure below I plotted the collected data. (To collect the data the phone was laying flat in the car facing the top of the phone to the…
riik
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7
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2 answers

Creating a 50hz comb filter in MATLAB

I have a signal in a 1d vector X, and I need to remove 50Hz and its resonant frequencies. I've looked into using fdesign.comb but I'm not sure how to apply that filter on my data (after building it using design). Alternatively, I think I can also…
Dororo
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What is a covariance matrix?

Suppose you have k samples from each of the N elements of a uniform linear array (ULA) of sensors: What is the physical meaning of a covariance matrix? How do you form a covariance matrix with the samples? How do you decide how many samples you…
random_dsp_guy
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How do I construct input to neural network from audio signals?

Input: Microphone recordings of digits from 0 to 9 from different speakers. Output: The digit from 0 to 9. I am doing this for fun. So first I will train my neural network using some samples and then use it to classify digits. Problem is every…
Pratik Deoghare
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How to apply watershed to segment images using matlab?

How to segment this image using watershed to retrieve only the people in the image ? I have done the following so far : Calculated a gradient Calculated the watershed transform My code: clear; I=imread('inpaint.jpg'); I=rgb2gray(I); hy =…
vini
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What is the difference between the Weiner-Hopf equation and the normal equation?

In adaptive filters, the development of LMS algorithm typically starts from the Weiner-Hopf equation, while the development of RLS algorithm starts from the normal equation. As I understand, these two equations are the same, and both their…
Joey
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What segmentation methods can be used for simple images?

As related to the project I am currently involved in, I have come to realize that one thing that might help is for me to 'segment' my image. To that end, I have shown a very simple example below. How do segmentation methods work in general, and…
Spacey
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Removing transients in highpass filtering with MATLAB

I've made a simple first order IIR highpass filter with a zero at z = 1 and a pole at z = 0.9. Its frequency response looks like this: Now, I filter a DC signal using this filter. Here's the MATLAB code I use to do it: b = [1 -1]; % Zero at z = 1 a…
Azura
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How to Apply Window Functions in Frequency Domain?

I am trying to apply a window function to smooth my signal and finally obtain the peaks of the signal. Yet, for spectral leakage I apply window function in time domain. After taking the Fourier amplitude spectrum ı want to further smooth the signal.…
madraperla
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