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# Questions tagged [group-delay]

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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)=... 1answer 52 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 ... 2answers 48 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 ... 1answer 106 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 ... 0answers 52 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 ... 0answers 55 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 ... 1answer 44 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,... 3answers 265 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.... 1answer 91 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 ... 2answers 41 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 ... 1answer 122 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 ... 1answer 87 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 ... 0answers 35 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 ... 2answers 250 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 ... 2answers 479 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 ... 2answers 471 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 ... 4answers 478 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 ... 1answer 210 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/2while maintaining constant magnitude everywhere. Group Delay is the ... 1answer 214 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 ... 1answer 293 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, ... 2answers 196 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 ... 1answer 141 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: $$H(e^{jw}) = \left\{ \begin{array}{ll} -j & \... 1answer 76 views ### average linear phase (group delay)- how can be calculated, given a signal samples at frequency F? Average linear phase (group delay)- how can be calculated, given a signal samples at frequency F? The definition doesn't help since the frequency is constant: -[signalPhase(n)-signalPhase(n-1)]/[... 1answer 698 views ### Compute group delay of an audio file from STFT I'd like to reproduce results from this paper in which the authors used Group Delay-grams as an input to the Machine Learning model. The Machine Learning side is not the one that I have problems with. ... 2answers 472 views ### How to compare many bandpass filters (for their signal propogation delay)? Let's say we have an audio signal sampled at 96 kHz, and we want to compare several bandpass filters to find the one with the lowest rectangular-envelope-propagation-delay (see graph below). The band ... 2answers 451 views ### Mean delay for a M tap harmonically weighted filter I am trying to derive the mean delay for M filter taps harmonically weighted:$$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 ... 0answers 68 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 ... 1answer 414 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 ... 0answers 1k views ### All pass filter design for group delay compensation I've designed an IIR bandpass elliptic filter in Scilab with the following parameters. Sampling Frequency = 25000 Hz Lower cutoff frequency = 100 Hz Upper cutoff frequency = 150 Hz Pass band ripple = ... 0answers 730 views ### IIR filter group delay I've designed an IIR bandpass elliptic filter in Scilab with the following parameters. Sampling Frequency = 25000 Hz Lower cutoff frequency = 100 Hz Upper cutoff frequency = 150 Hz Pass band ... 2answers 466 views ### Interpolated FIR filter group delay I'm trying to design a digital low pass filter with a narrow transition band. My sampling rate is 25 kHz, the cut off frequency is 60 Hz & the transition band width is 4 Hz. I'm looking for about ... 2answers 3k views ### Physical Meaning of Negative Group Delay for causal LTI systems I have implemented in Matlab (with minor variations) the example 5.1.2 "Illustration of Effects of Group Delay and Attenuation" I found in Alan Oppenheim's Discrete-Time Signal Processing 3rd edition. ... 0answers 79 views ### Interpretation of instaneous time and instaneous frequency in time-frequency plane? In this paper: Sparse time-frequency representations, Given signal x(t), the time-frequency representation was got by Gabor transform and was denoted by \chi(t,\omega)=|\chi(t,\omega)|\exp(\mathrm{... 1answer 70 views ### position of useful filtered data inside DFT based filtered output I'm trying to filter a 400 samples signal with various bandstop FIR filters (constant group delay), one at a time to see which one gives me the desired result. Every filter was build using the Kaiser ... 2answers 650 views ### Finding phase from group delay I know that group delay is defined as :$$\begin{align} \tau(\omega) = grd [H(e^{j\omega})] &=-\frac{d[\arg[H(e^{j\omega})]]}{d\omega}\end{align}$$But if what is available is group delay itself,... 0answers 60 views ### How to initialize shift registers in polyphase filter based resamplers to avoid or compensate for group delay? I have a signal a = [a(t0),a(t1),a(t2),..,a(tN-2),a(tN-1)] I'm using a polyphase filter based resampler with filter length L of 8, fixed interpolation rate I of 10000 and decimation rate of ... 3answers 382 views ### Group delay of H(\omega)= 1- re^{j \theta}e^{ - j \omega} I'm studying chapter 5 of Discrete-Time Signal Processing 3rd edition by Alan Oppenheim and I'm having serious difficulties understanding how he obtained equation 5.57. For those who don't have this ... 3answers 3k views ### Group delay of moving average filter I have implemented a moving average filter (in Python) where I fill a list with values and average them. When new values arrive the oldest will be deleted. Now I am wondering how much delay I get ... 1answer 302 views ### How to obtain a meaningful group delay graph using matlab Problem: I'm trying to analyze the behavior of an FIR filter with the following impulse response/kernel: Using Matlab's function grpdelay(myKernel,length(myKernel)), I obtained the following figure:... 1answer 755 views ### How to implement a FIR filter with correction of group delay on c#? I read respect to digital filters, and implemented both IIR and FIR filters and I found that this type of filters have a called "group delay". Now I know that the IIR have a non-linear group delay and ... 0answers 169 views ### How to design all-pass filter by specifying phase requirements? I want to delay the part of signal above (or below) specified frequency, but I don't find any books or tutorials to tell how to design is. The commonly used biquad APFs (such as the one introduced in ... 2answers 443 views ### How to Add Group Delay? I was confused about the value of group delay, I am not sure whether my opinion is correct. For example, if I want to add a group delay of 0.25 time units to a zero-phase signal, does it mean that I ... 2answers 282 views ### Showing linear-phase frequency response when only real part is known I'm studying for an exam, and this particular practice problem is missing the solution: Given a causal LTI system where only the real part of the frequency response is known,$$\Re\left\{H(j\... 1answer 2k views ### Differences between phase and group delay Yet another group delay vs. phase delay question! Though this is a question that's been asked several times I don't feel like it's been fully discussed so I'll post an example that I can't quite seem ... 1answer 552 views ### Group delay of the integrator I have a set of sensors, some velocity-meters and others accelerometers. To process the two groups together, I integrate the accelerometers signals (in time domain, using MATLAB's ... 1answer 3k views ### Interpolating/Decimating CIC Filter Group Delay I have an Interpolating Cascaded Integrator Comb (CIC) filter designed as so: Rate Change = 100 Number of Stages = 4 Differential Delay = 1 I'd like to calculate ... 1answer 611 views ### Group delay (MATLAB\tt grpdelay$) I have been trying to figure out how it is I have an IIR filter with large negative group delay. It's my understanding that if a filter is causal and stable, the group delay can't be negative at all ... 1answer 2k views ### How to remove a costant group delay? I have to subtract, from a signal x[n], its version filtered thorugh an LPF FIR filter, like this: xf=filter(h_lpf,1,x); y=x-xf; How can I remove the group delay introduced by the filter h_lpf into ... 1answer 238 views ### Lag in financial trading vs Group Delay in signal processing I'm a newbie to Signal Processing - and so I'm providing a "background" and a "question" section separately. Background: Suppose I have a linear filter (w.r.t. given as$\theta_{t+1} = \theta_t + ...
I have only magnitude spectra and group delay information and I need to sketch phase spectra from this information. For example, group delay is given like this: $\tau_{g}(\omega) = c$ where c is a ...