# Questions tagged [delay]

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### What effect does a delay in the time domain have in the frequency domain?

If I have a signal that is time limited, say a sinusoid that only lasts for $T$ seconds, and I take the FFT of that signal, I see the frequency response. In the example this would be a spike at the ...
• 693
7k 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 ...
• 225
455 views

### phase difference detection

For application of syncing sampling clock phase to carrier phase of received signal where the received signal is sampled with 10 times the carrier phase and modulated with the PSK shown in the figure (...
1 vote
8k views

### What exactly is a 90 degree phase shift of a digital signal in FM demodulation appraoches?

I am working on an FSK demodulator (1200/2200Hz, 1200 baud) featuring a 90 degree phase shift operation. I don't exactly understand what 360 degrees mean for a digital signal. My sampling frequency ...
• 125
2k 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 (...
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950 views

### Emulating a Variable Delay

I am trying to emulate a satellite link where the delay time between the satellite and ground station changes over time due to the satellite's motion. I plan do this by converting to the frequency ...
1 vote
892 views

### How to estimate the delay in time domain when knowing the phase shift in frequency domain

I am strugling with how to compute the exact value of delay in time-doamin when knowing phase shift in frequency domain. I have a analog circuit, I sweeped about 30 single tones frequency ranging from ...
1 vote
1k views

### Fractional Delay using Polyphase Filter

How to use rectangular window design to design a length-9 polyphase filter which delays an input signal by 3/5 of a sample? An expression for the 9 coefficients is required.
210 views

### How to use cross-correlation to verify speech data and determine delay

I have been experimenting with cross-correlation function to verify the presence of speech in a recorded file wrt a source file. I tried the following in Matlab: <...
7k views

### Is a notch filter for 50 Hz without delay possible?

I am processing an EEG signal (2 kHz sampling frequency) from hardware and the built-in filter doesn't work as intended. FIR gives a delay, and IIR is unstable. The signal of interest is from 4&...
• 273
8k views

### Measuring time delay of audio signals

Before anyone yells at me I fully realize that this question has been asked numerous times. I assure you that I've read through the existing questions and answers but I am still confused about part of ...
• 285
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### 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 ...
951 views

### GCC-PHAT always peaks at zero when estimating delay offset

My question is that when I used gcc-phat to estimate delay between two audio signals, it always returns zero offset. However normal cross correlation Xcorr gives a good result. I don't know the reason....
• 33
293 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 ...
• 1,414
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### 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 ...
2k views

### Implementation of a Variable Fractional Delay with Lagrange Interpolation using Farrow Structure

I am writing a C++ simulation software working in time domain. I generate regularly sampled data, and need them to be delayed, in "real-time", by a variable fractional delay. This is a pretty common ...
2k views

### GCC-PHAT (Generalized cross correlation) always peak at delay=0 on real audio signal

I have studied the GCC-PHAT algorithm to estimate TDOA on audio signals at 2 mics. Here is my MATLAB implementation: ...
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1 vote
229 views

### Filter design with 8-tap latency on recursion

I'm curious about the feasibility of designing a noise shaping filter (but might generalise to any recursive filter) with the constraint that the most recent output samples aren't available for ...
• 153
1 vote
814 views

### Time delay estimation using ultrasound

I have a sound source that generates an ultrasonic pulse. I have two microphones seperated by a distance which are at a distance from the source. I want to find the time delay of arrival of the ...
• 709
1 vote
247 views

### Matlab Pade approximation influence on bode plot and step response

I would like to approximate a delay via the pade approximation. I set a normal delay via the exponential term and I set a delay via the pade approximation and I look the difference between the both ...
• 145
1 vote
760 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 ...
• 817
1 vote
3k 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 ...
1 vote
1k 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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