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Questions tagged [fir]

FIR filters are filters with a finite duration impulse response.

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How should I modify my filter coefficients for the filter to be unaltered, when I change my sample rate

I am guessing this is a commonly encountered problem, but I am lost on how to really solve it. I have FIR filter coefficients that are used to match the frequency response of data sampled at 3 kHz. I ...
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1answer
43 views

Calculating filter coefficients of a Moving average with error correction

I have an oversampling ADC where I need to correct Gain/offset errors 'during' each conversion. This also links to my previous question - Moving average and linearization of two piecewise linear ...
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1answer
44 views

Digital filter design of time series for specified frequency response function

I am currently working with vibration measurements in structures. In the netherlands there is a guideline for verifying vibration measurements for damage to machinery. This is the so-called "SBR ...
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20 views

Why is my resampled signal cutoff when resampling with a windowed FIR filter in MATLAB?

I have an exercise to write a function which upsamples or downsamples a signal by a factor of F (integer) using a FIR filter windowed with a Kaiser window function. Exercise I had last week included ...
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12 views

GLP type three filter of order k, amplitude response?

Given a GLP type three filter of order K, with an amplitude response of |H(theta)|. I need to show that the number of real and causal FIR filters(identically different) of order K, with the same ...
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1answer
53 views

Explanation of FIR and IIR Filters with Simple Words

It seems I am unable to understand how these filters work and what is the point of using them, no matter how many tutorials I watched. Could someone please explain, in simple words, what FIR and IIR ...
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1answer
60 views

Numerical Calculation of impulse response out of frequency response

Currently I work on my Masterthesis which deals with structural dynamic simulation. As a part of it I have to filter a Signal with a FIR-Filter. From that Filter I know the Frequency Response (picture)...
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1answer
55 views

Hidden zero in system equation $H(z)$

An FIR linear phase filter has unit sample response $h[n]$ that is real with $h[n]=0$ for $n < 0$ and $n > 7$. If $h[0]=1$ and the system function has a zero at $z=0.4e^{j\pi/3}$ and a zero at $...
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33 views

Bandstop FIR Filter in Matlab

I need to design a Bandstop FIR filter and find its impulse response & frequency response in Matlab. I was thinking that, for the impulse response, I should filter my FIR filter with a delta ...
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2answers
37 views

What version of sinc function to use ? (With additional factor of $\pi$ or not.)

I have an exam tomorrow on Signal Processing and one of the questions can go two ways: Use a Hamming window to design an Nth th order (N+1 tap) band pass FIR filter with a pass-band between $f_0$-$...
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1answer
45 views

How to filter an OFDM signal? [closed]

Across the channel bandwidth there shoudd be 100 RBs (central 1200 sub carriers in a 2048 bin). Max power normalized to 0dB, the first OOB lobe should be -34dB. This 1st lobe on either side is at 5 ...
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41 views

What should be the cut off frequency of a Filter operating on an OFDM signal?

I have a time domain OFDM signal and to this I need to apply different linear filter however I am not sure on the cut off frequency. I am simulating for multiple symbols where each symbol has 1200 ...
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19 views

Constructing a lowpass digital differentiator such that maximum error is $n$ dB for passband

I want to construct a lowpass digital differentiator with uniform-interval samples such that error from ideal differentiator is $n$ dB in magnitude at maximum for the passband up to frequency $\...
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1answer
104 views

What exactly is Savitzky-Golay differentiation filter?

I could understand Savitzky-Golay filter as being smoothing filter, but then there also seems to be Savitzky-Golay differentiation filter, though for some reason, details do not seem to be clear. So ...
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2answers
74 views

Frequency response of numerical differentiation by polynomial interpolation / finite difference

One can use polynomial interpolation (or finite difference) to do numerical differentiation. However, there seems to be a surprising lack of interest in obtaining frequency response of this numerical ...
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1answer
31 views

Using Parks-Mcclellan (or others) for FIR differentiator?

I have never seen the use of Parks-Mcclellan for differentiator - most uses tend to be lowpass filters. Is this because Parks-Mcclellan implementation of FIR differentiator has numerical problems and ...
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2answers
41 views

Is Parks-Mcclellan algorithm guaranteed to stop?

Is there any guarantee that Parks-Mcclellan eventually stop? If so, is there any formula that shows number of maximum interations that ensure that the algorithm stops?
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1answer
40 views

FIR butterworth also possible or just IIR?

can we use butterworth and other such filters like chebyshev,elliptic etc with FIR or they can be only used with IIR?
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27 views

Group delay emulation in GNU Radio

I'm trying to test an equalizer against group delay distortion of a satellite communication link. According to the CCSDS standards, It is agreed to simulate high-order modulation system with in-band ...
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1answer
59 views

Design of FIR and IIR filters in Matlab

I need to create 4 different pass-band filters. What remains the same throughout is the following: Sampling Frequency = $3000Hz$ Pass-band Frequency = $900Hz-1200Hz$ Now, these are the filters I ...
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1answer
25 views

Deconvolve a FIR-filter using limits? Or: Are limits distributive with the inverse fourier transform?

Given $y[n] = f[n] * h[n]$ where $y[n]$ and $f[n]$ are two one-dimensional discrete signals that are given, find out: if $h[n]$ is a FIR-filter if it is a FIR-filter, what its kernel is. Obviously, ...
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2answers
74 views

How to efficiently control an FIR's magnitude response by altering its phase spectrum

Question: Extensively searching the space of all possible vectors of length $n$ to satisfy a (non-overdetermined) requirement is possible in principle. Hence, there is a way to calculate a complex ...
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40 views

FIR Audio Equalizer Crackling Noise

I've implemented a few FIR filters into a song equalizer, but there seems to be a crackling that I'm unsure how to fix. Heres a video for reference: https://www.youtube.com/watch?v=IlzWRYpv0rk. Noise ...
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1answer
45 views

FIR filter to delay signal [duplicate]

About filter design, mostly we want to control frequency amplitude response and the linearity of phase response. I wonder whether there are FIR filters specialized to delay signal? For instance, let'...
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1answer
41 views

Does a linear phase FIR filter shifted in frequency preserve linear phase?

Let's say I have a symmetric (and therefore linear phase) FIR low pass filter with real coefficients. If I then shift this filter in some direction in frequency by multiplying its coefficients with a ...
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215 views

How to find the impulse response of a filter, given the difference equation?

What is the impulse response of the system: $$ y[n]= \frac{16}{26T} \left(-\frac{1}{16} x[n] + x[n-2] - x[n-4] + \frac{1}{16} x[n-6] \right)? $$
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1answer
73 views

mpiir_l2(): Results are not IIR but FIR filters - why and how to avoid this?

I'm using mpiir_l2() from user Matt L's PhD thesis to design IIR filters. I set the number of numerator and denominator coefficients both to the same value (between ...
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1answer
40 views

Does the output signal from the FIR filter have transient response?

In matlab, I have shown the signal passed through the FIR filter in the time domain. Then the beginning of the signal is like the transient response. Is the result appropriate?
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2answers
63 views

Practical Least Squares FIR filter design: How to find a realistic desired response

I'm using Matt. L.'s lslevin.m function to design long ($N\approx 400$) filters to an arbitrary phase and magnitude specification. The specification is the result of a numeric optimization and does ...
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1answer
118 views

FIR design for arbitrary magnitude and phase: Why can I separate real and imaginary parts like this?

In this question about the design of a FIR filter with arbitrary magnitude and phase specifications user robert bristow-johnson suggested to split the desired complex frequency response $H$ into its ...
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1answer
70 views

Recursive form representation of FIR filter

Do we have methods to represent FIR filter in recursive form? One of the methods that I know is frequency sampling method. Can someone provide me any method?
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60 views

How to implement the RLS for matrices

I need to implement the RLS algorithm but it's for matrices instead for vectors, I have made the below code, but still something wrong is not working well, EDIT: The code should be done as below, ...
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1answer
36 views

3-tap FIR filter: simple expression for $H(e^{j\omega})$ using trigonometric identities

We have a linear time-invariant system described by the input-output relation $$y[n] = x[n] + 2x[n - 1] + x[n - 2]$$ Below is my approach to analyze this system. The impulse response of this system ...
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1answer
122 views

Low pass filtering of an upsampled(zero inserted) signal

I have been working on interpolation in python from quite some time. The input signal is a sinusoid signal sampled at 933KHz. I am upsampling the signal by a factor of 5 and later using an FIR ...
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1answer
90 views

Fast Optimization for Long FIR Filters

I need FIR filter lengths in the order of 1e4 and above to obtain reasonable accuracy in desired frequency response. The problem is that optimisation in MATLAB (e.g. fircls or the Optimization Toolbox)...
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1answer
111 views

What is the difference between closed form and opened form in z transform

I am new in DSP and I need to have a clear udrastanding about below example. Consider the below $h[n]$ as the impulse response of a system: \begin{equation} h[n] = a^n(u[n] - u[n-N]) \end{equation} ...
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181 views

Dithering adds harmonic distortion after filtering and upsampling

I have an issue which I wasn't able to solve for a few days. I have implemented a polyphase FIR interpolation filter within an FPGA which does interpolate by a factor of 8 or 16 times. I do accept an ...
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2answers
108 views

How to compare many bandpass filters (for their signal propogation delay)?

Let's say we have an audio signal sampled at 96 kHz, and we want to compare several bandpass filters to find the one with the lowest rectangular-envelope-propagation-delay (see graph below). The band ...
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1answer
157 views

What is an “innovation filter”?

I'm a math postgrad student working through a paper on eigenvalue decompositions of matrices of FIR filters (used for stuff like total decorrelation, convolutive mixing, MIMO). Towards the beginning, ...
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38 views

Parallel Cascaded FIR Filters

I have a relatively simple question. I know if you connect multiple LTI systems in parallel, overall system's frequency response is the sum of each LTI system's frequency response. Therefore, what ...
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1answer
89 views

Design of a complex FIR filter

For apply least-squares linear-phase FIR filter design,with frequency domain specification is not symmetrical. The pass-band error function, $$E(\mathbf{h})_p=\int_{\omega_{p_1}}^{\omega_{p_2}}| \...
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3answers
81 views

How to understand the filter coefficients in FIR filter

Here it is the difference equation we have: y(n) = -0.25x(n) - 0.15x(n − 1) + 0.78x(n − 2) − 0.15x(n − 3) - 0.25x(n - 4) I understand that is FIR. The ...
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4answers
774 views

Why is the first value in digital first-order IIR filter impulse response not the largest?

When I create a digital first-order IIR low-pass filter with scipy (code below), I get the following coefficients: B: [ 0.1367 0.1367] A: [ 1. -0.7265] The ...
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1answer
122 views

estimate the impulse response after equalization

I want to estimate the impulse response of the channel at the receiver. Assuming some arbitrary impulse response: h=[1 0.2 -0.4 0.0 0.6]. Once the equalizer is ...
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1answer
87 views

FIR filter design: evaluating the error function

Question 1 $$ H(e^{j\omega})=\sum_{n=0}^{N-1}h[n]e^{-jn\omega} =\mathbf{c}^H(\omega)\cdot \mathbf{h} \tag{1} $$ $$ =\mathbf{h}^H\cdot\mathbf{c}(\omega) \tag{2} $$ $$H(\mathbf{h})=\sum_{k=1}^Kh[k]e^{...
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42 views

Is this a FIR algorithm?

I'm kind of out of my element here trying to understand this algorithm and I wanted to see if this is a FIR algorithm or not? If this isn't the right place to ask this, can someone point me to a place?...
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1answer
177 views

Design of FIR filters with arbitrary magnitude and phase responses

I found many information in this thesis "Algorithms for the Constrained Design of Digital Filters with Arbitrary Magnitude and Phase Responses",i want to understand it. This question is a ...
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1answer
48 views

Arbitrary-Response Filter Design

I want to design a FIR filter by using 'cfirpm' function , which can i use the group delay and grid frequency, my code is : ...
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1answer
56 views

FIR filter design and implementation meaning [closed]

What is the output of the convolution meaning which is used in the FIR filter? how can conclude the output of the FIR filter in the output according to the input $x[n]$?
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2answers
211 views

Mean delay for a M tap harmonically weighted filter

I am trying to derive the mean delay for $M$ filter taps harmonically weighted: $$y[n] = \frac{M\,x[n] + (M-1)x[n−1]... + 1 \cdot x[n−M+1]}{\tfrac12 M (M + 1)}$$. For a uniformly weighted filter, I ...