Questions tagged [group-delay]

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Phase compensation using IIR allpass filters

As an exercise with IIR allpass filters, I am trying to compensate the phase of a lowpass Linkwitz-Riley filter using the Matlab integrated function iirgrpdelay. The code I am using is the following: <...
skateskate's user avatar
2 votes
1 answer
90 views

How to calculate and compensate group delay caused by channel and how to define group delay to wideband signal?

Suppose a wideband signal is sent and received by a RX. If different frequency components travel in different speed then there exists group delay in the signal, right? Not consider the multipath ...
Xiang Li's user avatar
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How does rate reduction work in a decimator with even valued gain?

Cascaded integrator-comb (CIC) filters are used in decimators, and decimators with a gain that is a power of 2 are popular (at least at my workplace) because the gain can be normalized with a right ...
DavidG25's user avatar
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1 vote
1 answer
255 views

IIR Filter order vs group delay

From what I understand FIR filter order is same as it's group delay because of the linear phase and every frequency being delayed by same amount. For IIR filter, filter order only tells that filter ...
doubleE's user avatar
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2 answers
120 views

Possible error when finding group/phase delay in scipy

After designing a "least square optimal" FIR filter I wanted to find the group/phase delay, defined as: $P(\omega) \triangleq - \frac{\Theta(\omega)}{\omega}$ (Depending on the literature ...
Casper's user avatar
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3 votes
1 answer
229 views

Group delay and number of zeros for a symmetric FIR system

I am studying for an exam and need help on a question on the study guide. The question is given below. A symmetric FIR system $h[n]$ extends from $n=7$ to $n=11$. a) What is the group delay? b) How ...
AdamsK's user avatar
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1 answer
99 views

Link between maximum delay of cross-correlation and phase velocity

I try to express the relation between: the delay obtained by maximizing the cross-correlation between two signals $x$ and $y$ noted $\tau_{x,y}$ and the phase velocity noted $v_p(\omega)$ In the ...
User327201's user avatar
1 vote
0 answers
97 views

Cascading IIR filter with All pass filter (APF) for constant group delay and linear phase over the passband using MATLAB not working?

I've designed an IIR Low pass filter in MATLAB with the following parameters. ...
Md. Hasan Rahman's user avatar
1 vote
1 answer
144 views

Slope of phase function

Would appreciate some help understanding if I take the phase function of some transfer function and derivative it in the linear part of it which is around the resonant frequency what does this slope ...
wonder3's user avatar
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2 votes
0 answers
35 views

Does flat group delay bandwidth of a Thiran filter increase with increase in filter order?

Experimentally, it does seem that for a Thiran allpass delay filter of desired low-frequency group delay $D$ with filter order $N$, increase in filter order $N$ increases bandwidth of the frequency ...
John Luke's user avatar
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58 views

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 ...
John Luke's user avatar
2 votes
1 answer
104 views

Stability of N-order Thiran delay filter when required passband delay is N+1

In this lecture note, on page 7 (or page 111, the same page), it is said that the Thiran allpass delay filter of order N with passsband delay N+1 reproduces samples with zero error. I find it hard to ...
John Luke's user avatar
6 votes
1 answer
256 views

Alternative derivation for a Thiran filter

Following this reasoning (link on ee.se) I'm trying to derive the transfer function for a Thiran filter, but I get stuck. I know of the original paper, I just thought I'd go this way. This is what I'm ...
a concerned citizen's user avatar
5 votes
2 answers
379 views

Group delay compensation for non coincident drivers

Suppose I have a two-way speakers system which can be modeled as a two-way Linkwitz-Riley crossovers network with impulse responses $h_{lp}(n)$ and $h_{hp}(n)$. I would like to equalize the group ...
Spark123's user avatar
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1 answer
80 views

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 ...
gg h's user avatar
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Issue Understanding Time Delay of a Digital Filter

I am new to the world of digital filters and am educating myself with the book Introduction to Digital Filters by J.O Smith III,. The author derives the frequency response of a very simplistic filter: ...
afp_2008's user avatar
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1 answer
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Is the filter $1/(1-s)$ anti-causal?

The filter with the response function $$ H(s) = \frac{1}{1 - s} $$ Produces a positive phase shift and a negative group delay for all frequencies Is it anti-causal? Is there a way to deduce such ...
Crataegus's user avatar
1 vote
0 answers
37 views

Group Delay of a GLP [closed]

I am trying to understand what is the Group delay from a given figure. I was given an assignment with the following figure: and was asked the following: "what is the group delay (in the passband ...
Ameed's user avatar
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0 answers
47 views

Audio crackles with delay in series

I am learning to write audio plugins using VST3 sdk. I have an issue implementing 2 delays in serie, the audio starts crackling. Here is the processing code: ...
Abitbol's user avatar
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1 answer
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Varying shift between microphone data

I had given a sine wave of frequency 2kHz as input to two microphones placed near to each other. The data grabbed by two microphones are then plotted in MATLAB and it was found out that the initial ...
Deepa's user avatar
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How do large tap counts effect FIR Filters for block data?

I am using the ARM CMSIS DSP library for a signal processing application. I find good filter performance when using tap counts that are in excess of 10% of the length of my data block. I understand ...
FooAnon's user avatar
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1 vote
1 answer
187 views

FM demodulation using complex differentiation

I'm trying to implement the complex differentiation discriminator which is taken from Software-Defined Radio Using MATLAB, Simulink, and the RTL-SDR. The final result is $$s(t) = \frac{s_q'(t) s_i(t) -...
S.H.W's user avatar
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1 vote
1 answer
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can $e^{j\phi_0}$ be incorporated into the sine and cosine terms?

This is from "communication system" by Carlson fifth edition page 109: If transfer function of a channel be like this: $H(f)= Ae^{j\phi_0}e^{-j2\pi ft_g} $ and input to this system be: $x(t)=...
m-sh-shokouhi's user avatar
1 vote
1 answer
85 views

RF-Chain Signal Delay for Sensor Switching

Lets have a RF-chain as above with system bandwith from HP corner to the green line say 1 MHz. The signal accumulates delay as it passes through this analog chain, and due to it being non-liner filter ...
BandW's user avatar
  • 105
1 vote
2 answers
734 views

Designing digital low pass filter with low pass-band group delay

I'm interested in specifying a digital low pass filter with low (and near constant) pass band group delay. I tried python's spicy.signal.minimum_phase to transform ...
rhz's user avatar
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2 votes
1 answer
532 views

What is the relationship between group delay and propagation delay for a filter? [duplicate]

I was trying to design a filter for a system and I was able to obtain the group delay plot in matlab using grpdelay. The group delay output is in samples. However, I was not able to relate that data ...
arun_kol's user avatar
0 votes
0 answers
150 views

Matlab group delay not corresponding to reality

I studying effects of digital filters group delay (IIR). In Matlab there is a function grpdelay which allows for particular frequency get a value of delay in samples But after filter applying and ...
the_jack's user avatar
2 votes
0 answers
296 views

Stability of filters with negative phase delay, group delay, and positive phase

Lets assume I have an IIR filter with : bz = [1.0195 0 0]; az = [1 0.0166 0.0020]; fvtool(bz,az) The filter is stable as i can see. If you check the phase delay ...
BandW's user avatar
  • 105
1 vote
1 answer
113 views

Group Delay of Mulitrate system

how do I find the group delay of multirate system.(sample rate converter) , IIR non-linear phase filter Say decimation by 2 (with lpf) = tf1(num,den) then again decimation by 2 (with lpf) = tf2(num,...
BandW's user avatar
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1 vote
3 answers
2k views

How to practically correct for group delay imposed by a digital filter (Python)

I'm using Python to filter a signal using a Butterworth filter (scipy.signal.butter) and subsequently passing this through a forward-backward filter with cascaded second order sections (scipy.signal....
Cazador's user avatar
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0 votes
1 answer
181 views

Design FIR with linear phase response

What is the best way to design a FIR filter with a given linear phase response, such that each frequency inside the passband is phase shifted according to: $$H(f)=e^{i2\pi f k}$$ where $k$ is factor ...
FIRphaseLIn's user avatar
0 votes
2 answers
146 views

Bandpass with large group delay

I read that a simple delay filter that delays all frequencies requires at least $\frac {N-1} {2f_s}$ taps. In my case this would result in way too many taps (20000). Can I achieve this with ...
filternoobie2020's user avatar
0 votes
1 answer
350 views

Group delay plot of a Moving average filter

I am implementing the moving average filter in Matlab. Using fvtool on this filter, gave the following output curve, is this group delay curve correct? Edit: My confusion is regarding the values of ...
varungupta's user avatar
1 vote
1 answer
173 views

Group delay of non differentiable unwrapped phase

As we know group delay as a function of frequency, computed as differentiation of unwrapped phase, but what happen at those frequencies where unwrapped phase is non differentiable?how to calculate ...
user215805's user avatar
0 votes
0 answers
73 views

Estimation of Group Delay from Noisy Frequency Response Measurements

Consider a linear, time-invariant system. Noisy measurements of the magnitude and phase associated with the frequency response of the system are available over some dense generally non-uniform grid ...
rhz's user avatar
  • 375
1 vote
3 answers
951 views

How do you calculate the group delay in samples of a Biquad Filter at a given frequency from the coefficients?

If I have a BiQuad all-pass filter with a given set of coefficients such as: g: 0.903228 a1: -1.88142 a2: 0.903228 B1: -2.08299 B2: 1.10714 And my operation per ...
mike's user avatar
  • 447
8 votes
2 answers
1k views

Negative group delay and envelope advance

I am having a doubt reading about delays in signal processing. Let there be an input to a LTI system with frequency response $H(f)$, given signal $x(t) = a(t)\cos(2\pi f_ot)$, where $a(t)$ is a ...
Dsp guy sam's user avatar
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0 votes
2 answers
2k views

Calculate the time delay introduced by group delay for IIR-Filters

First of all, let me show what I mean by a simple example of an FIR-Filter: I designed an FIR-Filter with a constant group delay of 323 samples and my sampling rate is 500 Hz. Now I can calculate the ...
Stephan's user avatar
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4 votes
4 answers
3k views

What is meant by "Group delay" in simple words?

Although likes of this question have been asked many times on DSP SE But i am unable to understand those and i wish to have a crystal clear explanation in simple words with example The only thing ...
DSP_CS's user avatar
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5 votes
1 answer
382 views

Group Delay for Hilbert Transformer and Resulting Dispersion

An ideal Hilbert Transformer shifts the phase for all positive frequencies by $-\pi/2$ and all negative frequencies by $+\pi/2$ while maintaining constant magnitude everywhere. Group Delay is the ...
Dan Boschen's user avatar
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1 vote
1 answer
422 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 ...
Irreducible's user avatar
3 votes
1 answer
762 views

Compensating the Group Delay of an Analog Filter using DSP

I am having a problem in my current project where I need to measure different biological signals (like ECG) simultaneously. As the instrumentation hardware is developed by different people over time, ...
falsterbo's user avatar
  • 141
2 votes
2 answers
424 views

Measuring group delay through a linear phase filter

I'm having a difficult time wrapping my head around a phase/ group delay problem and it corresponding to where you start sampling so I built up a system to test some of these issues. The system passes ...
nada's user avatar
  • 21
0 votes
1 answer
225 views

Ideal Discrete Time Hilbert Transformer with constant group delay

Let's assume we have an ideal discrete time Hilbert Trasnformation system (90-degree phase shifter) with a frequency response over one period: $$H(e^{jw}) = \left\{ \begin{array}{ll} -j & \...
MJ13's user avatar
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-1 votes
1 answer
83 views

average linear phase (group delay)- how can be calculated, given a signal samples at frequency F?

Average linear phase (group delay)- how can be calculated, given a signal samples at frequency F? The definition doesn't help since the frequency is constant: $-[signalPhase(n)-signalPhase(n-1)]/[...
student's user avatar
3 votes
1 answer
1k views

Compute group delay of an audio file from STFT

I'd like to reproduce results from this paper in which the authors used Group Delay-grams as an input to the Machine Learning model. The Machine Learning side is not the one that I have problems with. ...
Colonder's user avatar
  • 143
2 votes
2 answers
650 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 ...
g6kxjv1ozn's user avatar
2 votes
2 answers
574 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 ...
Srilakshmi Alla's user avatar
0 votes
0 answers
79 views

The grid frequencies In the design of a digital filter

I want to find many difference 'h' with same group delay and length filter using this code : https://gist.github.com/mattdsp/17f508d2b368db61f47689e4622d8841/c1518f22a5aa451951601b56c5d9f72743868bfe ...
K.n90's user avatar
  • 141
0 votes
1 answer
679 views

Compensating for group delay in FIR with symmetrical coefficients

Suppose I have a sinusoidal signal of 50Hz sampled at 6.4kHz and I wished to filter it at: Band pass: 160Hz, Bands stop: 800Hz, Apass:0.1db, Astop: 106db For a FIR filter order of 40 I would get 41 ...
almost_linear's user avatar