# Questions tagged [delay]

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### 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 ...
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 ...
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.
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: ...
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 ...
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. ...
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 ...
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 ...
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 (...
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 ...
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 ...
247 views

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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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"?
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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?
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 ...
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 "...
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 ...
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 ...
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 ...
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 ...