# 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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### How to implement the recursive FIR filtering of a signal with zero boundary condition?

Now I have a signal $f(k)$ with $k=0,1,\ldots, N-1$, and $f(k)=0$ if $k<0$ or $k>N-1$, that is, the signal satisfies the zero boundary condition. Then by convolving this signal with a symmetric ...
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### Why does applying fir filter in R (gsignal package) increase the magnitude of all values?

I am new to signal processing and I am sure this is a very rudimentary question. However I have done various searches and I cannot find an explanation (possibly because my knowledge is insufficient to ...
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### OBC DA FIR Filter Implementation

I understand the theory of Distributed Arithmetic and its application in FIR Filter implementation to avoid the excessive power consumption in the multiplication operations But a question here, when I ...
132 views

### Decimation filters: IIR vs. FIR

I just read this article on decimation filters. In particular, in section 2.3.3 it is strongly suggested that FIR filters are advantageous, because you only need to calculate every $M$th sample, where ...
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### How to solve attenuation caused by filter coefficient quantization in Matlab?

Before quantization of filter coefficient, it behaves well, but after quantization the amplitude drops to 0.52186, which is expected to be 1000(fig.1). But according to the amplitude response in ...
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### Designing a prototype filter for a DCT-filterbank

I want to create a prototype filter as in A Kaiser Window Approach for the Design of Prototype Filters of Cosine Modulated Filterbanks. I want to create a filter of length 2*M with M = Number of ...
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### Transposed FIR filter: Alternative binary tree structure

As part of an exercise, I have been assigned to find an alternative method of executing the additions of a transposed FIR filter. There is a hint stating that the alternative method should be in a ...
1 vote
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### FIR filter phase response at fs/2

I am currently building a FIR filter based on frequency sweeping data (0 Hz to Fs/2), i.e., transfer curve in frequency with the sampling rate of Fs. The phase response is shown in the following ...
1 vote
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### Matlab Filter Designer "Filter Information" shows wrong order

I want to design a low pass filter using the Filter Designer tool of Matlab. The filter order should be 10. I chose the Blackman window method and specified the order of the filter. However, "...
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### A problem on FIR filter design given a difference equation

Given the following difference equation: $$y(n)=2x(n-2)+3x(n-5)$$ describing the structure of an FIR filter, design the direct form of one. What is the order of the filter? ...
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### Filter type selection for signal envelope detection

Working on a signal envelope detection code in Matlab in which an RF signal envelope is to be created. The flow is such that filtering is performed according to the detected presence of a signal in a ...
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1 vote
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### How to create a frequency weighted measurement? / How to design a Pinking FIR Filter?

Disclaimer: I have read a lot about signal processing, but I taught everything myself and therefore have some gaps in theory and practice. I am currently working on a measurement software that is ...
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### Convert filter coefficients at one sample rate to different sample rate

I was doing some research into dithering in audio, and I was always wondering what Audacity's "Shaped" dither was. Well, turns out it's noise shaping, with an FIR filter whose coefficients ...
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### For continuous systems that in Quasi-static / Static Equilibrium are Memoryless?

A. BACKGROUND: Apparently this question’s answer says this some static systems have memory especially those that hysteresis: Confusion about 'memoryless' meaning So the word static to me ...
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1 vote
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### Can sampling rate impact filter output?

I am noticing that the behavior of equalizers in music softwares varies depending on the sampling rate. If we apply a filter (IIR or FIR) to a digital signal, in what situations does the sampling rate ...
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### Finite/Infinite Impulse Response filters

Most image filters are of finite extension (which correspond to Finite Impulse Response in 1 dimension), like Laplacian, Canny, Gaussian... Instead of being of infinite extension (IIR in 1D). Why is ...
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### Why fir1 from MATLAB returns one more sample than its order?

I'm starting to use both the fir1 MATLAB and firwin Scipy functions. Both are window-based FIR filter design methods. I would ...
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### Numerical optimization method for optimal edge detector

John Canny, in his paper "A Computational Approach to Edge Detection" (PDF), finds the expression of an optimal edge detector by first using an analytical approach (Euler-Lagrange equation). ...
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### Constrained Least Squares Filter Design

I would like to design a complex FIR filter, $h$, for a known signal that produces a desired output: $d$ = $s*h$ (where $s$ is my signal and $d$ is the desired filter output). Let $S$ be the ...
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### Generate FIR filter coefficients from Mag and Phase response

I have the target filter response in the form of (bin #, value) for every fft bin, for Magnitude and Phase. As an example, (bin 100, +12dB) for Magnitude and (bin 100, -90 degrees) for Phase. How do I ...
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### FFT-based fast convolution vs IIR filtering

I'm doing an multichannel audio equalizer system on a chip, which is parametric EQ, usually implemented in cascaded biquad IIR filters. My problem is that I use a lot of IIR filters due to multiple ...
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### What's the interpretation of this Low pass filter spec?

From the filter characteristic mentioned in the table, is it correct to interpret following for LPF: Fs=192Khz Passband edge=43.8Khz; passband ripple=5mdB Stopband edge=112Khz; stopband attenuation=...
1 vote
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### Why is the attenuation of the cut-off frequency 6dB in MATLAB filter Designer?

I am new to FIR filter design. I have a question about the MATLAB filter designer. I notice that the attenuation at the cut-off frequency is fixed at 6dB. So if I want my attenuation to be 3dB, what ...
1 vote
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### FIR FIlter pipelining

Does pipelining a 3 tap FIR Filter change the output of the filter? I understand the output stays the same but how do I prove that? I am a little confused as we add two more delay elements and am not ...
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### Having a hard time understanding FIR filter transverse structures

I'm currently learning about FIR filtering from one of my modules and went through topics such as transverse implementation(or structures since I could not find transverse implementation on the net) ...
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### How to determined the cutoff frequency of a IIR or FIR

I am trying to design a IIR to remove the noise from my input signal. Here is my the my input signal in the frequency domain And here is the noise in the frequency domain that, So I may choose ...
1 vote
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### What are these mysterious spike after the FIR filter?

The main paramter of this fir filter in flowgraph: Decimation：1 Cutoff freq:8KHz Transition width: 1KHz I have a very simple FIR test in Gnuradio ,the flowgraph is below: When I change the signal ...
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### Does a FIR filter $H(z)$ with maximally flat passband group delay response satisfy $|H(e^{i\omega})| \leq 1$? [closed]

From this paper (Maximally flat low-pass FIR filters with reduced delay) and others, I know that it is possible to impose maximally flat passband group delay response constraints. Suppose that I do ...
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### Find the Transfer Function from Magnitude and Phase Response

We can use common algorithms such as what is available in firls and firpm in MATLAB for least squares or minimax fitting to ...
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### A real-time (causal, non-symmetric) lowpass FIR filter with minimal passband ripple and phase

I am looking for a lowpass FIR filter that is causal (all samples used are current or past) and exhibits very low passband ripple and has passband phase very close to zero, which necessitates a filter ...
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### Formula to compute FIR and IIR Filter coefficients

I am trying to understand filter design. I am trying to implement butterworth filter which would have high,low and bandpass using the difference equation representation for FIR and IIR. Given the low ...
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### Frequency filtering in the frequency domain vs. time domain

As a DSP newbie, I've stumbled into doing band pass filtering (of pre-recorded IQ data) in the frequency domain - which allows brick wall filtering (I'm just setting the IQ values of each consecutive ...
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### Parallel decimating FIR

I'm trying to implement a parallel decimating FIR targeting an FPGA. The data rate is 4x the FPGA clock speed so I am receiving 4 separate streams of the demultiplexed data stream. I need to decimate ...
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### Symmetric half-band FIR re-timing

I'm trying to get my head around an FPGA implementation of a half-band FIR filter. I'm trying to draw the block diagram to help with that. I've started with a 10th order example as so: Due to the ...
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### Does FIR filter remove DC offset properly?

I was checking FIR and IIR filter for offset removal. But I found that FIR can not remove DC offset properly. I think there's something more to do with the filter coefficients of FIR to remove DC ...
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### Interpolation FIR filter output spectrum

I've inherited some FPGA code implementing an interpolation by 2 with a FIR low pass filter. The code came with a cocotb test bench that also models a filter (scipy.signal.lfilter) and then compares ...
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### Convolution between bit stream sampled by N number of samples per bit with a channel modeled as low pass filter

I generated a bit stream in MATLAB, from the transmitter to be convoluted by the channel I use MATLAB function "randi" between 0 & 1, so it generates random vectors of 0s & 1s and ...
1 vote
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### Fractional Delay in Matlab Scale Signals

I am trying to write a function which takes an input signal and delays it by a non-integer index. The function is based on the ideal bandlimited fractional delay filter technique, already available in ...
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### Remez function equivalency between Matlab and Scipy

I've read the similar question Find the equivalent of this python remez specs in C++ remez or Matlab firpm, which describes a different problem. In Matlab, I have following ...
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### How to design fir filter from transfer function

Transfer function is this equation in frequency domain: $$G(f) = \frac{1}{4\pi d} e^{i2 \pi d f/c}$$ or Hankel function d : constant (distance), c : 340 We may think we know complex number of ...
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### Best way convert transfer function to FIR filter without group delay if i have complex transfer function data

when i calculate acoustic transfer function, system identification using adaptive fir filtering is usually used and that have not tap/2 group delay maybe. in simulation if i have complex number of ...
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### non-causal cascade filtering process in frequency domain

if i have linear filter that operate in frequency domain filter length is L (Overlap and save method) if there is no computational time, i get L input signal and fft and multiply filter and ifft the ...
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### How to implement the direct form of FIR filter if in the transfer function there is no poles and power of z's are positive?

I confuse about the implementation of the FIR filter with no poles. If the transfer function is given in the form $$H(z) = 1+az^{-1}+bz^{-2}$$ direct form implementation is just delay operator ...
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### How to determine the transfer function of the second order FIR filter?

I need to find the transfer function of the second order FIR filter. I searched a lot in the standard textbooks, but I could not get the mathematical expressions and derivations. I want that the zeros ...
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### If i have arbitrary complex number what is the best method to make filter

i have equation like for example A(W) = isin(2pi*w) in frequency domain (it can be anything) that have arbitrary amplitude and phase response. i usually make symmetric structure in real part and ...
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### Integer v Fractional ADC outputs with FIR Filter Inputs

I have a system I'm working on that inputs an 18 bit ADC output into an FIR filter on a Xilinx FPGA. I'm a little concerned I may be representing the numbers wrong. My ADC outputs a signed 18-bit ...
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### Arbitrary shape frequency response filter [duplicate]

i want to make arbitrary shape digital filter from equation. that have own magnitude and phase response. the equation is bessel function. the frequency response is below zero phase and real value and ...
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