Questions tagged [delay]

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1answer
264 views

Finding audio signal time delay: cross-correlation vs. impulse response?

I need to find a time delay between the two audio signals, one comming from one set of speakers, and the other being the source signal that is initialy sent to speakers. I send some noise through ...
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1answer
1k views

LTI system $y(t)=x(t-T)$ with or without memory

How can I verify if the LTI system ($T$ is a real number, $y(t)$ output, $x(t)$ input): $$y(t)=x(t-T)$$ is with or without memory? I know that, if $y(t)$ depends only on $x(t)$, the LTI system will ...
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0answers
94 views

Why prediction by AR model causes time lag

Why does prediction by AR model cause a time lag? Please tell me why theoretically.
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1answer
341 views

Compute Power Delay Profile (PDP) from Delay Spread

I have data pertaining to channel obtained from measurements. In order to make use of this data, I need to convert it into a form as follows: ...
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1answer
318 views

Time variance of $y(t)=x(2t)$

At first I had trouble proving the time variance for this as I would do the usual mistake as in question Is the system represented by the equation $y(t) = x(2t)$ time invariant?. The solution has ...
1
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0answers
115 views

How to find and fix the delay of a modulation

I am creating a model in MATLAB to simulate power line communication, but I found a problem. I'm very new to the DSP area, I get my code below from a MATLAB example. ...
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1answer
238 views

Successive dynamic time warping with a set of window sizes

I am applying DTW to a set of data. I haven't figured out a solution yet, still searching for ideas, and I'm currently trying to apply DTW successively with a monotonic set of windows. Let's say i ...
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2answers
227 views

Dynamic Time Warping of inverted binary signals

I am trying to find a match between a reference binary signal and a large set of data. From experience, the reference signal can appear time-shifted(that is why I've chosen dtw) and inverted, meaning ...
6
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2answers
939 views

Flat fading criterion of OFDM subcarrier spacing

I have always thought that the OFDM subcarrier spacing $\Delta f$ is chosen such that not too small because Doppler spread can destroy subcarrier orthogonality not too large to avoid Cyclic Prefix (...
0
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1answer
438 views

Maximum likelihood estimator of active time delay and passive time delay

A typical time delay estimation problem has the model: $$ \begin{align} x_1(t) &= s(t)+ n_1(t) \\ x_2(t) &= a s(t-D) + n_2(t) \end{align} $$ Where $n_1$ and $n_2$ are considered to be ...
2
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2answers
669 views

Confused with filtering linear chirp signal using band-pass filter

everyone. Recently, I am doing simulations about filtering a linearly chirp signal, and have been confused about the result. The signal was linearly chirped from 0 to 1000 Hz. At first, the chirping ...
2
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1answer
247 views

Regarding the advantages of generalized linear phase filters

I know that for a linear-phase filter with frequency response given by $$H(e^{j\omega}) = |H(e^{j\omega})|e^{j\phi(\omega)} $$ if the input of the system is $$x[n] = s[n]\cos[\omega_0 n] $$ where $s[...
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0answers
52 views

Finding lossless coefficients to multi-tap feedback delayline

I have a digital delayline code which looks like this: ...
4
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1answer
772 views

Time delay estimation in low SNR

So I am interested in finding delay between two noisy narrowband signals,for example, two arterial pulse waveform. I can easily get a correct estimate of delay using cross-correlation method, but it ...
2
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1answer
55 views

Books on delay / lag compensation

Which books do you recommend that provide comprehensive overview of delay compensation techniques in control systems?
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0answers
449 views

Finding lag times for multiple time series

I have $N$ time series which have unknown time offsets relative to each other. I want to estimate the $(N - 1)$ time offsets, $\tau_{i,i+1}$, which maximise the sum of the cross-correlations between ...
-1
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1answer
91 views

Modeling an infinite delay system

If black holes swallow everything and assumes that the black holes do not get out the things from them, then can we consider a black hole as an infinite delay system? It takes the input and it is a ...
6
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3answers
828 views

Digital delay effect: avoiding clicks on delay time change

I'm implementing a digital audio delay effect using a simple circular delay line. Changing the delay time by making the delay line longer or shorter introduces discontinuities in the audio signal, ...
1
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2answers
1k views

Determine Phase Difference and Time Delay Between Two Pulsed Sinusoidal Signals

I am working on a code that generates two signals: A pulsed sinusoidal signal ($1\textrm{ MHz}$) beginning at $0$ phase, and lasts for say $5\ \mu\text{s}$, then trails zeros. The other signal has the ...
1
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0answers
36 views

How to conserve symmetry of discrete spectrum after applying fractional delay in the frequency-domain? [duplicate]

Imagine a real-valued, discrete-time signal $h[n]$ with $N$ samples and a sampling period of $T_s = 1/f_s$. We know that the DFT of the signal $H[k]$ is conjugate symmetric because the signal is real-...
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2answers
242 views

Filters applied separately to right and left channel of stereo microphone yielding inaccurate results

I must estimate the direction of arrival of an acoustic source, and I hope to distinguish between a voice input and musical input using a frequency cutoff. In order to do this, I apply the same ...
6
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4answers
5k views

How to calculate a delay (correlation peak) between two signals with a precision smaller than the sampling period?

I would like to calculate a delay between two signals in MATLAB. Normally, I would do this with a cross-correlation (xcorr), and then calculate the position of the ...
0
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2answers
7k views

Phase shift between two signals

So I got some oscilloscope captures for a project I'm doing and I'd like to find a phase shift between them because I don't trust the scope calculation. So I extracted data from a .csv file and ...
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3answers
725 views

How to design a digital filter with a frequency dependent phase delay?

I want to design a filter with a custom phase delay related to frequency. As frequency increases, phase delay should increase. The time delay as a function of frequency can be expressed as: $t_d = \...
1
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1answer
820 views

Causal and Non-causal filtering. Strange behavior

I'm trying to understand the behavior of a causal filtering exemplified by figure below. This behavior is making LDA (Linear Discriminant Analysis) misclassify our data, by clearly reverse the signal ...
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3answers
625 views

Continuous phase for phase delay calculus in FIR filters

I would like to estimate the phase delay accurately for any random FIR filter. The definition of the phase delay is the continuous phase divided by the angular frequency (with a sign change). That ...
1
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1answer
462 views

Designing a discrete-time inverse system

I am trying to design a discrete-time inverse system to eliminate an undesired echo in a data transmission problem. The echo caused by the transmission channel is represented as attenuation by a ...
1
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0answers
687 views

When do you use a minimum-phase filter over a linear-phase filter

Q1) I have understood that linear-phase filters have more delay time whereas minimum phase filters implement a lesser delay time but introduce phase distortion artifacts which linear-phase filters ...
0
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1answer
1k views

Real-time delay between signals

I currently have a real-time noise suppression algorithm based on two inputs from different microphones. It has passed most tests that I have thrown at it, however when the signal I am trying to ...
0
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2answers
224 views

Interpolated impulse response for fraction delay?

I need to find a way to create some fractional delay in a signal processing application that I am working on. Separately to this, I have been messing around with basic filter design (despite reading ...
1
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2answers
598 views

Farrow fractional delay filter - Range of delay?

I am implementing a fractional delay for resampling purposes, using the Farrow structure to enable continuously variable delays. For now I am simply using windowed sinc functions as my low-pass ...
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2answers
511 views

What's a “delay line”?

I know what a delay is, but what's a delay line? What's the reason for calling it a "delay line"?
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3answers
777 views

How do delay lines create so many effects?

I was trialing this audio plug-in from SonicCharge (there's a program demo in the site). It claims to be based on a delay line and uses some logic to modify it: At its core is a 12-bit digital ...
3
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2answers
232 views

Are there equations for placing sounds in the stereo field using delays?

I'm thinking of the typical stereo widener (haas, binaural) effects here, those that extend from the typical pan knob to create "out of the headphones" -experience. These processors can be automated ...
1
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1answer
366 views

Fractional/Interpolating Delay Line still sounding glitchy

I'm trying to implement a simple digital delay line. I want it so that when the user changes the delay amount, it sounds smooth and not glitchy. Currently I'm implementing a fractional delay line but ...
0
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1answer
143 views

Applying a window to input signal

I am sorry if I say any thing silly .Please forgive me.I want to apply a window to input signals.I have two signals each of which contains zeros (462 samples) and non zeros data (38 samples).I want my ...
2
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1answer
116 views

Processing and feature extraction from very short signals

I recently have encountered very short time signals (from three to 12 samples, typically). They appeared for instance in small time frames in engine simulation that should be extrapolated in a robust ...
3
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1answer
1k views

Emulate tape delay

I'm trying to emulate a tape delay in a VST plugin, but I'm not sure how to handle the delay changing? I want it to sound like a tape is actually fast forwarding/rewinding. Most digital delays I've ...
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2answers
2k views

How to perform a time domain shift in the frequency domain without zero padding

Apologies in advance if my question doesn't make sense. I'm not the most fluent person in signal processing. I have an array of time domain values that I would like to apply a time delay to by ...
2
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2answers
2k views

How to generate realistic echo to sounds?

I guess the most straightforward way of adding an artificial echo to a sound signal is to add its time-delayed version to the original signal. However, I am not sure how realistic that would sound ...
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2answers
156 views

Delay signal according to normal distribution

I am trying to delay a signal by a certain number of samples. This certain number, I would like to generate using a random normal distribution in Matlab. I am using the following for generating the ...
1
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1answer
490 views

What is the difference between transport delay and dead time?

I am confused on what the difference between transport delay and dead time is. They seem to have the same function, but I'm not sure. Can someone explain the difference if there is one?
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1answer
674 views

FMCW SAR chirp return from target modelling

I have to Model a chirp signal that was return from a Distance D from target and then multiply with the reference transmitted signal. Which will give me beat frequency signal and then fft to get the ...
0
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1answer
860 views

How to design a delay and sum beam former with fractional delay less than one sample?

I am supposed to design a delay and sum beam former for a short audio. But the sampling frequency is only 8kHz and after times the delay, the fractional delay is less then one sample, and after the "...
1
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2answers
621 views

Distorted output of delay VST effect in C

I'm getting some odd results with some code I'm working on. Help me with the implementation of this delay effect? The code takes an input, adds delayed input to it and then passes it to the output ...
4
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3answers
3k views

Cross correlation with short or non periodic signals?

I am a total newbe to signal processing and i have a problem which may be quite trivial to most of you guys. I want to align two short sensor signals (speaking of max. 1000 samples recorded with ...
2
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1answer
463 views

Low order sinc interpolation vs. polynomial interpolation for variable fractional delay

I'm implementing a variable fractional delay element for use in online audio processing. Applications include ie. Karplus-Strong synthesis, flanger, chorus, echo, vibrato. I'm not oversampling, so ...
1
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1answer
709 views

Allpass filter feedforward/feedback design and code

I want to design/implement a simple feedforward/feedback all-pass filter, and I am having some troubles and questions with it. From Shroeder design (based on J. Smith article here): I came up ...
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2answers
206 views

Emulating guitar pickup position with delays

If I have a vibrating string, then there will be no motion at the endpoints. If I move away a bit from an endpoint then I'll get a signal, but particularly the fundamental will still be attenuated. ...
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0answers
826 views

Why does a phase shift in the frequency domain not produce a time delay in the time domain?

Suppose I have an input signal which represents a vehicle front suspension response that has been measured using an accelerometer. It is seen that the measured rear suspension response is effectively ...