Questions tagged [finite-impulse-response]
A finite impulse response (FIR) filter is a type of a signal processing filter whose impulse response is of finite duration.
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Why is the frequency measured in radians in filter design?
This is my first time posting a question, so sorry if my articulation is not proper.
I'v just started out with FIR filter design and I see the domain being -$\pi$ to $\pi$. Now I understand that ...
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Decimating Polyphase Filter in Simulink
I have read many of the articles on the website regarding a polyphase decimating filter structure. I'm sure we are all familiar with the typical image shown in Fred Harris Multirate book and many ...
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Transfer function coefficients and impulse response - FIR filter
I am currently working on a FIR filter (varying in time). I have the real coefficients of the filter, but I would like to know if they correspond to the coefficients from the impulse response (as $b[k]...
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chromatic and polarization mode dispersion compensation in electrical dmain
I am currently working on adaptive compensation of chromatic and polarization dispersions in the electric domain using LMS (least squares method) and CMA (constant module algorithm) algorithms.
I am ...
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The parameters of tolerance scheme of a FIR filter
in the first part of the problem they told us that an FIR filter with impulse response h[k] ( z-trafo H(z) l should be designed to the following parameters.
And then in the second part it says that ...
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Polynomial division to separate FIR and IIR in cascade
I have a FIR filter $L(z)$ and an IIR filter $H(z) = \frac{B(z)}{A(z)}$ which are cascaded together as $L(z)H(z) = L(z)\frac{B(z)}{A(z)}$.
For specific reasons I want to calculate a parallel topology ...
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Building a FIR filter from an arbitrary frequency-magnitude response curve (eg. Least Squares fitting) [duplicate]
I'm trying to create a FIR filter from a magnitude equation, where my starting equation provides the magnitude (amplitude) between 0 and 1 for any given frequency in Hz.
I posted the magnitude ...
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Designing ideal lowpass filter in the form of FIR
How to design a ideal lowpass filter by cutoff frequency of Ļ/4 in the form of FIR filter by 64 samples using matlab?
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Algorithm to Count Zeros Outside Unit Circle for FIR Filter
As detailed in this post Can I set a constraint on the first tap of an FIR filter such that its inverse is stable? I show how Cauchy's Argument Principle can be used to easily confirm if an FIR filter ...
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Can I set a constraint on the first tap of an FIR filter such that its inverse is stable?
Let's say I have the following FIR filter $h[n]$, so the output $y[n]$ for an input $x[n]$ is
$$
y[n] = \sum_{k=0}^{m-1}x[n-k]h[k]
$$
The inverse of this filter is given by the IIR difference ...
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Simplifying frequency response equation
I am trying to to find a magnitude and phase response of a FIR filter as in problem 5.18 Digital Signal Processing 4th Edition by John Proakis. I got the frequency response as:
$$
H(\omega ) = 1 - e^{...
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How would you put this “IIR Approximation of FIR Filters Via Discrete-Time Vector Fitting” into Matlab? [closed]
https://www.eee.hku.hk/~culei/publication/ISCAS-0590.pdf
This paper talks about a way to approximate FIR filters using IIR via a method known as Discrete-Time Vector Fitting. I am confused on how I ...
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Examples where non-linear phase filters are used
I stumbled apon this old question:
Why is a linear phase important?
There the explanation of why linear-phase processing (filtering) is important is very clear. Also the effects on waveforms due to ...
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Real-time audio processing FIR vs IIR
My project consists in filtering an audio signal from the microphone, in order to remove noise, and find the time distance between two peeks with the highest precision possible.
I understood that an ...
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1answer
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Is there a way in MATLAB to approximate an FIR filter using an IIR Filter? [duplicate]
I am a student trying to understand how this is possible. I've done some research on the web with not many sources showing up with solutions to this problem that are usable. What techniques are used ...
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What is the need of IIR filter? When FIR have generally good/desirable characteristics?
FIR filters are generally stable and have linear phase response. These two characteristics are often desired in dsp
So why do we need and use IIR filters,despite the fact that IIR filters often have ...
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Meaning of Phase response of a filter? In simple words?
What is meant by phase response of a filter? Often it is associated with restoration of signal shape,so if a filter has linear phase response, its output looks like input otherwise output is ...
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1answer
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Implementation of Filters in Python
I've implemented 2 filters in Python I would like to know if they look OK or not.. I've implemented an lowpass FIR Hann Filter and an lowpass IIR Chebyshev type 1 filter. My plots look like the ...
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1answer
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Can't implement correctly Python IIR and FIR Filters
I'm trying to implement 2 lowpass filters and see the difference between them from plots( one FIR filter that needs to be designed with the Hann window method and another IIR filter using Chebyshev ...
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2answers
101 views
Lowpass Hann filter in Python
I'm trying to design a FIR lowpass filter using Hann windowing in Python but I don't know where to start from... I have fc1,fc2, ft, rp and rs as parameters. This is my Python code:
...
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3answers
89 views
Box filter with non integer length
I'm trying to model a sensor system that has an averaging behaviour. The frequency response is almost identical to a box filter and looks roughly like this:
Transferring this into a discrete time ...
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1answer
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Approximate IIR filter with FIR filter with energy restrictions
Hi I was presented with this problem I would like some guidance to solve:
I am given the following DT channel model:
$$C(z) = 1-0.3z^{-1}$$
I am first asked to design an IIR linear zero forcing ...
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3answers
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Moving average filter magnitude attenuation
I am dealing with a moving average filter which filters power system signals to rid them of noise or harmonics etc. The fundamental or useful component of these signals is centered around 50 Hz or 60 ...
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1answer
56 views
Noise Reduction Moving Average FIR
I read that the noise reduction of a moving average FIR can be expressed as the square root of N where N is the length of the filter.
How do you prove? I can't quite get it.
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FIR Filter - Low Pass Filter coefficients to High Pass filter coefficients
I need to convert this 12 Tap Low Pass Filter to a High Pass Filter.
The coefficients of the Low Pass Filter are as follows:
...
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1answer
70 views
Output length of an IIR Filter
In general, the output length of an FIR filter is given by (N+M-1) samples, where N stands for signal length and M stands for the number of filter coefficients. Can the same formulae be applied for ...
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1answer
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FIR Filter implementation without padding
Is it possible to implement FIR filtering action without padding the input and coefficients?
i.e. Let's say if the input and filter coefficients are of size 4, then the output will be 7 samples. So, ...
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1answer
56 views
FIR Filter implementation vs Linear convolution implementation
I came across a C code for the FIR filter on one of the websites. It is as follows
...
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1answer
27 views
Adaptive equalization vs inverse of transfer function
I have the following equalization problem as shown in the figure below:
Now I can compute the coefficients for my adaptive FIR filter c (dim(c) = N) the following:
$\mathbf{c_{opt}} = (\mathbf{H}^T\...
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2answers
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Calculating phase shift between two sines of equal, unknown, amplitude and frequency
I've got a source signal $s_1(t)$ and a system affecting that, yielding a phase-shifted version $s_2(t)$;
\begin{align}
\color{blue}{s_1(t)} &= A\sin(t+\phi_1)\\
\color{red}{s_2(t)} &= A\sin(...
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1answer
57 views
CIC SINC3 Filter with unsigned Integrators
I want to use the AD7401 Sigma delta modulator connected to my FPGA.
The Datasheet pg.15 has some demo verilog code which I understand alright except one thing:
They use unsigned integers for all of ...
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FIR coefficients from complex frequency response with regards to sample rate
I have trouble understanding how the sample rate of a DSP system is taken into account when creating FIR coefficients from a complex frequency response.
I work with Jupyter and Python 3.7. The ...
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1answer
89 views
What is the slope of a transfer function?
Lets say I have a Transfer function (H) plot as below. I need to find the SLOPE of the transfer function in dB/MHz.
That is... i need a plot (db/MHz) vs frequency.
How can i go about it ?
...
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0answers
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FIR Filter Magnitude Response
This is the shape of the bipolar amplitude function for a FIR filter with odd m:
I have 2 questions :
If i want to use this FIR as a low pass filter between 0 and $\frac{F_{c}}{2}$ , how can i set ...
0
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1answer
59 views
FIR Linear Phase Condition
This is the linear phase condition for FIR filters as expressed by my prof:
I don't understand why $G(f)$ can be negative. Isn't the Fourier transform expressed in polar form ? So the magnitude is ...
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2answers
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Does a raised-cosine filter have infinite support?
I recently asked a question here regarding limiting the bandwidth of a digital baseband signal and was introduced to pulse-shaping using a "raised-cosine filter". At the time, I mistakenly assumed ...
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1answer
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Question about zeroes of simple 2nd order FIR filter
I have a question about the zeroes in a simple second order FIR filter. I'll list out the major beat points of calculating where the zeroes are before asking the question (I'm following "Designing ...
0
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1answer
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Strange Response of a fir1 Filter in Matlab
i have been tinkering with some fir filters to bandpass-filter a signal. Even though the filter looks pretty descent in frequency domain, i receive a quite strange "filtered" signal in time-domain. I ...
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2answers
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Meaningful output of FIR filter output
I have implemented FIR filter using tapped delay line method. I start getting output as soon as first input sample is passed to it, I am wondering from which sample I will get the proper output(...
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1answer
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How to chose a kernel function for a FIR low pass filter in audio processing?
As the answer of a previous question, I was suggested to use a FIR filter to act as a low-pass filter to reconstruct the envelope of a sound wave (edited, emphasis mine):
As I said in a comment, ...
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3answers
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How to use a FIR on a signal with a drifting central frequency?
I have been working on this subject for a while and I couldn't get a proper answer.
I am trying to estimate the phase of the input signal :
$x(t)=Ae^{j(at^2+bt+c)}+n(t)+i(t)$
Where $n(t)$ is a ...
0
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2answers
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how a signal for which calculate RMS can be filtered and have a fast settling time?
i designed a sinusoidal pwm amplifier (3KHz to 20KHz) that regulates its output voltage reading the RMS value of output current.
The RMS is obtained squaring the signal sampled by AD converter @...
2
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1answer
640 views
Number of taps needed in an FIR filter to remove DC
An FIR filter is being used to remove the DC of an ECG. The sampling rate is 500Hz. How many taps would said FIR filter require (theoretically and practically) to filter out the DC.
P.S. the filter ...
3
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1answer
126 views
FFT strong signal in middle frequency bin
I've developed a radar that I'm using to determine the distance to remote objects. It uses a custom PCB with an onboard FPGA that performs the DSP algorithms. The data from it is then plotted on a ...
0
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3answers
182 views
How to reliably compute the group delay of a comb filter
I applied the following FIR comb filter in real-time:
y[n]=x[n]-x[n-40]
Since this is an FIR, the group delay is D=(N-1)/2=20 samples. After applying the filter ...
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1answer
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FIR filter format - Brutefir - Volumio
I am trying to compensate for the high frequency droop of a TDA1543 based nos DAC. One straightforward method is described here.
Having played the resulting .wav, ...
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1answer
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How to Determine if FIR has a Linear_Phase Response w/o Matlab
Given the FIR transfer function:
h(z) = $ .36 + .384z^{-1} + .1608z^{-2} +.9712z^{-3} + .352z^{-4} + .18z^{-5} - .2z^{-6} $
How do you determine if this transfer function has a linear - phase ...
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1answer
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What exactly is stored in “output” variable in the FIR Filter code below? [duplicate]
What exactly is stored in "output" variable in the FIR Filter code below?
...
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1answer
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What are the limitations of FIR filters?
I know that for type II FIR filter it adds a zero at $z=-1$ so it cannot design a high-pass filter.
My question:
what type of limitations the other types have (type I, III, IV)?
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1answer
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What exactly is stored in the buffer array in the code below? Is it the values of x[n-k] or something else?
What exactly is stored in the buffer array in the FIR Filter code below? Is it the values of x[n-k] or something else?
...
