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Time delay vs phase ramp, group delay and phase delay

I need to apply a phase ramp in the frequency domain to a signal in order to apply a delay to it in the time/digital domain. However, I am confused by the fact that if I convert the phase ramp into ...
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2 answers
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Linear Phase in equiripple filters

How come equiripple filters are symmetric/anti-symmetric in time, but do not posses linear phase, but only piecewise-linearity? Do not all FIR+symmetric/anti-symmetric have Generalized linear phase?
Processor48's user avatar
2 votes
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217 views

Phase response of non-symmetric FIR filters

FIR filters are said to have linear phase when the filter coefficients are symmetric or antisymmetric with respect to time instant n=0. I am trying to design a ...
Deepa's user avatar
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2 answers
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Turning non-symmetric filter into a symmetric filter

I would like to ask if there is a systematic way to turn a non-symmetric filter into a symmetric equivalent with the same frequency response. For example, let's say I have a finite length filter with ...
AAM's user avatar
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FFT-Phase variation of a signal

I was studying the phase variation of a signal using sliding window FFT generated using below python code. The phase variation produced for my signal starts from somewhere in middle of the signal ...
Arjun Chaudhary's user avatar
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Derivation of the 4 types of real-valued linear-phase FIR filters

Is there any resource or literature where I can find derivations/proofs for all four linear phase filter types starting from an arbitrary real valued impulse response? I looked at some of the ...
user avatar
3 votes
5 answers
503 views

Linear phase with a non-integer delay?

Let's say you are given a frequency domain specification for a filter design. As a simple example, let's use an ideal (brickwall) LPF. Now the impulse response of an ideal LPF is a $\operatorname{sinc}...
Ahsan Yousaf's user avatar
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What is the position of all zeros of a minimum phase, Type 1 Linear Phase FIR Filter?

Let me write down all the facts that I know of. In context of the z plane: Minimum phase system: All zeros and poles of such a system lie inside the unit circle. Linear phase FIR filter: For every ...
McSuperbX1's user avatar
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Linear phase impulse response causes non linear phase frequency response in GNU Octave/ Matlab

Assume linear phase FIR symteric impulse response like [1 2 3 4 5 5 4 3 2 1],shoud resault in a frequency response with linear phase negative sloped phase. but it ...
mohammadsdtmnd's user avatar
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Parallel connected FIR filters type III

I am currently studying dsp and I have a question: Let us assume multiple FIR filters with generalized linear phase of Type III and real IRs $h_1[n], h_2[n], ..., h_k[n],$ interconnected in parallel. ...
Νεφέλη Γαρουφαλή's user avatar
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2 answers
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Why does an FFT-based filter change phase?

I am very new to DSP, and I'm just trying to figure stuff out here. I saw a video which stated that a filter implemented using an FFT would alter the phase of different frequencies differently. The ...
kepe's user avatar
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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
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Phase of an FFT after zeropadding

How does zero padding effect phase of an FFT? I thought that symmetric zero padding in the center of an image or signal produces no phase change in the FFT (See Here), but I am getting different ...
DarkLink's user avatar
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1 answer
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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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Difference between MSK and CPSK

I'm trying to understand the differences between the MSK and CPSK transmission, but I am not understanding some things about it. I understood that they are two signals without discontinuity, but what ...
Riccardo Barbo's user avatar
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1 answer
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Matlab: How to design digital equivalent for a lowpass Bessel filter (Thiran filter)?

In the process of applying a lowpass Bessel filter to my signal, I realized that besself function does not support the design of digital Bessel filters and the bilinear function can be used to convert ...
Amy 's user avatar
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subquestion 2 : original Q "Difference between MSK and GMSK?"

if we talk about a modulation, we mention a linear and nonlinear modulation. GMSK is nonlinear modulation, but it can be derived from a linear modulation as MSK, PAM and we talk about a linear ...
FrimHart64's user avatar
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Why can't quantum phase noise in radio astronomy amplifiers just be filtered out after down conversion, instead of down-converting first?

In the related Astronomy SE questions below and their answers, it has become apparent that radio telescope arrays down convert their highest frequency bands before the first stage of amplification. ...
uhoh'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: ...
shashashamti2008's user avatar
1 vote
2 answers
151 views

Frequency Sampling Filters (FSFs) NOT the Frequency Sampling Method

A class of digital filters called Frequency Sampling Filters (FSF) has been mentioned in a side note by Richard Lyons in another related question comparing IIR digital filter design using mapping ...
Dan Boschen's user avatar
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13 votes
4 answers
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Minimum Phase - All Pass Decomposition For Large Linear Phase Filters

UPDATE: I am looking for a robust approach to decompose linear phase FIR filters with 100s of coefficients into its minimum phase and all pass components. I originally thought determining all the ...
Dan Boschen's user avatar
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2 votes
1 answer
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Combination of type I FIR linear-phase systems

Let $h_1[n]$ and $h_2[n]$ be impulse responses of type I FIR linear-phase systems with lengths $M$ and $N$. What can be said about the phase response of the following filters? $h_3[n] = h_1[n] + h_2[...
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2 votes
0 answers
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Equivalence between the linear phase of FIR filters and the (anti)symmetry of the coefficients

According to the Matt L.'s answer to this question, real-valued and causal FIR filters have a (generalized) linear phase response if and only if their coefficients satisfy (anti)symmetry condition. ...
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Arbitrary phase FIR filter design

I would like to design an FIR filter using the frequency sampling method with nonlinear phase specifications. For example, between $0$ and $\frac{f_s}{4}$ a phase of $180^\circ$ and between $\frac{f_s}...
A7mad Ali's user avatar
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1 answer
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Determine group delay from the frequency response of FIR filter

I have a issue to find out, is there any way that one can determine a group delay from frequency response of the FIR filter. Let's say I have I type FIR filter with order of 51. Frequency response ...
Gal_Anonim's user avatar
1 vote
1 answer
497 views

What is the significance of the linear phase in the phase response of an M-point moving average filter?

I have plotted the magnitude and the phase responses of an M-point moving average filter, the following are the plots when M = 10: We can observe that corresponding to every lobe in the magnitude ...
Aditya's user avatar
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6 votes
3 answers
1k views

Delay a signal in time vs in frequency

I have a signal h that I want to delay for a time t. I know that I could use two possible approaches: $h_{\text{delay}}[k] = \...
Mattia Surricchio's user avatar
2 votes
1 answer
907 views

What is the reason behind complex conjugate pairs in Linear Phase FIR filter analysis from the Pole Zero plot

When we say that a Generalized Linear Phase System must satisfy the pole zero plot with the condition that a complex zero not on the unit circle exist's in a pair of 4. Then I understand that I need ...
Power Surge's user avatar
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3 answers
409 views

Does converting an FIR filter from causal to non-causal remove phase delay?

Let's say I have a causal 3-tap FIR filter: $$y[n] = ax[n] + bx[n-1] + cx[n-2]$$ Assuming I have access to all the data prior to filtering and generate a similar non-causal filter: $$y[n] = ax[n+1] + ...
Izzo's user avatar
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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
1 vote
1 answer
648 views

Resampling FIR coefficients

I have received from a client a 32-coefficient FIR filter running at 1 kHz. I would like to adapt the filter to a 24-coefficient FIR filter running at 750 Hz while preserving the 0-375 Hz frequency ...
Ben's user avatar
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1 vote
1 answer
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What is the phase response of SRRC/NRZ/RZ pulse shapping filters and does it matter?

So I would like to know if filters usually used for pulse shaping (like SRRC) have a linear phase response, and if not, what this response looks like and does it matters in any circumstances?
graille's user avatar
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2 votes
1 answer
750 views

How should we read FIR filter phase response graph?

What should we see from the FIR phase response graph, as an example for a linear phase? And what does this straight line at $0.5\pi$ mean?
Ece Su Ildiz's user avatar
3 votes
1 answer
431 views

Applications for the Maximum Phase Filter

A maximum phase digital filter has all zeros outside the unit circle, and has the maximum phase and therefore longest delay for a given magnitude response. Besides the possibility of needing a ...
Dan Boschen's user avatar
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5 votes
1 answer
1k views

Why can't realisable IIR filters have linear phase?

I am studying IIR Filter Design and came across this arbitrary statement in my textbook which says that 'physically realisable and stable IIR filters can not have linear phase'. Would really ...
Devesh Lohumi's user avatar
1 vote
2 answers
1k views

How to properly smooth the phase of a spectrum (or any unit-complex function)

I want to smooth the phase of a measured (transfer) spectrum without destroying unit-complexity of the phase factor. Suppose $$f:\mathbb{R}\to \mathbb{C}\qquad , \qquad f(\omega)=r(\omega)\cdot {\rm e}...
oliver's user avatar
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7 votes
4 answers
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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 ...
Todor Petkov's user avatar
1 vote
1 answer
734 views

FMCW radar: Linear phase change determination with sinusoidal decomposition

I am struggling to understand how linear phase shift can be determined with a transform whose main purpose is to determine frequencies rather than rate of change of a function. In FMCW radar, ...
Raj's user avatar
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0 votes
2 answers
1k views

How does one make a Zero Latency, Linear Phase, or Natural Phase filter?

Looking at FabFilter's ProQ3 plug-in, they have an option at the bottom of the window to switch between Zero Latency and Linear Phase modes (and I think a Natural Phase option too). I'm familiar with ...
ImJimmi's user avatar
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1 answer
714 views

Is this phase response linear phase?

Would the following frequency response be considered linear phase? I know that linear phase is when the phase response is a linear function of frequency. However, the phase response is only linear ...
Jimmy Vailer's user avatar
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1 answer
597 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 ...
themagiciant95's user avatar
0 votes
1 answer
102 views

Constraints for Type 3 Linear Phase Filter

This might be a strange question - but most of the Type 3 LPF I'm seeing are having this in common for $h[n]$, assuming $h[n]$ is real: We cannot have outermost element of h[n] lower than middle ...
Arun Prasath's user avatar
5 votes
1 answer
461 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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0 votes
1 answer
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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 ...
dsplearner's user avatar
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1 answer
1k views

Finding remaining zeros of linear phase FIR filter

Question given is: if $h(n)$ is a linear phase causal FIR of order $10$ with real coefficients, find the remaining zeros of this filter if the zeros given are $$q_{1,2} = -2 \pm 2j$$ $$q_{3} = -\...
S'Danc's user avatar
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4 votes
2 answers
816 views

Linear phase FIR filter for impulse responses that don't appear symmetric

I would like to clarify some confusion I have about linear phase FIR filters of which do not seem to have symmetric impulse responses. Starting with a simple case, a delay, $ h[n] =\delta(n-n_0) $ ...
DarkLink's user avatar
  • 307
0 votes
1 answer
2k views

How to prove a filter has linear phase response?

I have designed an FIR filter to have linear phase response using odd-symmetry design. The coefficients of this filter are {2,1,3,1,0,-1,-3,-1,-2}. I am now being asked to prove it has linear phase ...
Rebecca Meagher's user avatar
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1 answer
2k views

Is ideal band pass filter (brick wall filter) linear phase? [duplicate]

I'm very new in digital signal processing. I have multiple sensors and the way I filters the signals in post processing is: take FFT of the signals. put zero on out range of interesting frequency (...
Jeong Won Kim's user avatar
1 vote
1 answer
199 views

Phase plot of $H(e^{j\omega})=(1-re^{-j\omega})\left(1-\dfrac{1}{r}e^{-j\omega}\right)$, $0<r<1$

I want to find the phase plot of $H(e^{j\omega})=(1-re^{-j\omega})\left(1-\dfrac{1}{r}e^{-j\omega}\right)$, $0<r<1$ for the interval $0\leq \omega \leq \pi$. Method 1: $H(e^{j\omega})=1-\left(...
Narendra Deconda's user avatar
2 votes
1 answer
2k views

Downsampling impact on complex phase

For my application, I have to downsample a bandpass complex signal which spectrum is located on the second Nyquist zone. Knowing that this processing will cause a spectrum inversion, what would be ...
M.FAKHFAKH's user avatar