Questions tagged [delay]
The delay tag has no usage guidance.
99
questions
3
votes
1answer
97 views
Maximum cross-correlation coefficient value for time delay estimation
I am using cross-correlation for time delay estimation of two synchronized recordings ($x_1$ and $x_2$) of a fixed sound source from two different locations.
I understand that the delay is associated ...
1
vote
1answer
32 views
Plotting phase delay from first principles giving different result from phasedelay() function. Why?
I have a length 10 Finite Impulse response as shown below, and I am trying to find the phase delay of this FIR.
$$h[n]=\begin{cases}0.1,& 0\le n \lt 10\\
0,&\textrm{otherwise}\end{cases}$$
I ...
0
votes
0answers
26 views
Mathematical expression for a system
I have a system that delays the input with k samples and concatenates the new input with delayed one so that y = [x(n) x(n-k)] so if the input comes with n samples the output should be k+n samples. ...
1
vote
0answers
50 views
Implementing real-time variable fractional delay line in Matlab
I am attempting to implement a fractional delay line in Matlab which operates in real time, uses an object-oriented approach, and whose length can be modulated each time a sample is processed. I have ...
0
votes
2answers
87 views
Delay in Savitzky-Golay filtering
I am applying a Savitzky-Golay filter to a signal, using the scipy function.
I need to calculate the lag of the filtered signal, and how much is it behind the original signal.
Could someone shed ...
1
vote
0answers
41 views
Time delay estimation of signals increasingly decorrelated
The problem may be summarized as follows: I have a stochastic signals and I want to measure an increasing delay, as depicted in the following picture. The picture represents the signal as it is being ...
0
votes
1answer
283 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:
...
0
votes
1answer
100 views
What is the meaning of inverse signal bandwidth?
I have been studying the two ray model in communication systems.
The text I'm studying has two signals, $u(t)$, which is Line of Sight and $u(t-t')$, which is the reflected signal.
It quotes,
...
0
votes
1answer
160 views
90 Degree Phase Shift / Rotation Algorithm for SDR
I'm working on a library to preform frequency demodulation from an SDR signal. I'm using https://github.com/sysrun/rtl-sdr/blob/master/src/rtl_fm.c as a crib for this. The algorithm starts by taking ...
3
votes
1answer
61 views
Is it possible to design a band-pass filter with fewer taps than a series HPF + LPF?
I am digitally filtering a signal that is streaming live. The goal is to reduce the filter delay as much as possible while maintaining the quality of some measurements based on the filtered signal. ...
0
votes
1answer
42 views
How to correct a QAM time delay
How can you correct the anticlockwise rotation that occurs in the received constellation of a QAM system?
My only idea is to compensate the delay with an advance but this is impossible since you ...
0
votes
1answer
24 views
What is the z-domain transfer function of variable delay?
Is it possible to obtain the transfer function of a signal that has a variable delay?
For instance, I have a signal consisting of 10 samples:
0,1,1,1,1,0,0,0,0,1
If I would apply a unit delay to ...
1
vote
1answer
97 views
FIR filter to delay signal [duplicate]
About filter design, mostly we want to control frequency amplitude response and the linearity of phase response. I wonder whether there are FIR filters specialized to delay signal?
For instance, let'...
0
votes
1answer
60 views
Findin the source direction using cross-correlation function
I am new to DSP and I'm working on the following problem.
We have a sound source in the far field and a microphone array consisting of two microphones with distance d. We want to determine the source ...
0
votes
1answer
88 views
difference equation block diagram delay or advance confusion
When does the unit delay, become unit advance essentially.
Goal is to deduce difference equation from block diagram.
Green text is notes about what the value should be in that node of the diagram.
...
2
votes
1answer
323 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 ...
0
votes
2answers
2k 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 ...
1
vote
1answer
250 views
digital IIR filter delay and oversampling
Can oversampling decrease the delay of digital IIR filter? Imagine there is some digital signal going into processor that applies low pass filter.Lets say its 1 KHz sample rate and the filter is ...
0
votes
1answer
34 views
Dynamics processor for speech - apply gain on delayed samples?
A Dynamics processor (limiter, compressor, expander, and gate) is calculating the output gain at some point in time, and it is applying this gain at some delayed point in time.
This allows for ...
0
votes
1answer
133 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 ...
0
votes
3answers
204 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.
0
votes
1answer
188 views
Converting Time Shift to Phase Shift
I have just started taking signal & systems lessons and here is my question:
If we say that x0(t) = A.cos(w0t). (a cosine signal with zero phase shift, w0 ...
0
votes
0answers
86 views
Bandpass Fractional Delay Filter
I am designing a fractional delay filter, I found this code for lagrange FIR fractional delay filter, The fractional delay filter acts as a low pass filter, it passes low frequencies from 0 to 0.25*fs....
1
vote
1answer
321 views
How to calculate the delay generated by a 2nd order all-pass filter
I'm trying to simulate the dispersion effect of a stiff string in a digital waveguide system, by using second-order all-pass filters.
I use a second order all-pass filter with this transfer function:...
2
votes
0answers
118 views
How can I oversample the received signal by double of sampling time and have two signals
I have a question, how can I make the sampling in Matlab for the received the signal by half of time duration of symbol (Ts), and have two copies of signal (that's the process of fractional sampling ...
1
vote
0answers
243 views
Time-Delay beamforming delay computation
I'm trying to implement a beamforming algorithm in python and I'm stuck with the time-delay computation for a rectangular array.
I'm using the following equation to compute the delays based on the ...
0
votes
1answer
142 views
Audio transfer function modelling with pink noise + signal
I'm trying to model a transfer function for a noisy audio system, specifically to measure delayed system response. Before I can confidently apply control, I need to verify that I can exert control ...
0
votes
2answers
65 views
Calculation of autocorrelation - does calculation “loop”?
With a delay $l$, autocorrelation is defined as:
$$r_{xx}(l) = \sum_{n=-\infty}^{\infty}x(n)x(n-l) = \sum_{n=-\infty}^{\infty}x(n)x(n+l).$$
I want to calculate the autocorrelation of a signal
$$x(n)...
2
votes
1answer
315 views
How to calculate a delay between two signals in frequency domain?
Calculation of a delay between two signals is generally done by finding the maximum in the cross-correlation of the two signals (in time domain):
$$
\tau_{delay} = \arg\max_\limits{t}(f(t) \star g(t))
...
1
vote
0answers
90 views
Sensor fusion under unknown correlations: can covariance intersection account for delays?
Of late, there has been some interest in cooperative estimation algorithms in robotics, where the information sources are usually sensors such as cameras. When multiple robots observe surrounding ...
0
votes
2answers
70 views
audio signal time delay estimation(TDE) in indiviual and separate mics
common TDE problems algorithms(such as GCC) often require audio signals in different mics concurrently, however, is it possible to estimate audio signal time of arrivals(ToA) in different mics ...
3
votes
0answers
58 views
Minimum time delay that can be estimated between two sensors
Consider a 1-dimensional toy problem. I have two sensors at different points along the $x$-axis. Somewhere away from the sensors, a disturbance is created which travels towards the sensors, first ...
2
votes
1answer
158 views
Can a unit delay in discrete time be represented by exponential functions?
If we have a signal $y[n]$ and its unit delayed version $y[n-1]$, can we write $y[n-1]$ in terms of $y[n]$ times some exponential?
The reason I want to do this is to then take $y[n]$ common and ...
1
vote
1answer
65 views
How to quantify delay in filtered output?
I have a signal containing two sine tones 30 kHz and 60 KHz. I used a second order IIR notch filter to filter out the 60 KHz component from the signal, so now the signal has only 30 KHz component.
...
1
vote
1answer
176 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 ...
1
vote
1answer
552 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
0answers
85 views
Why prediction by AR model causes time lag
Why does prediction by AR model cause a time lag?
Please tell me why theoretically.
0
votes
1answer
252 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:
...
0
votes
1answer
232 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
vote
0answers
102 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.
...
0
votes
1answer
199 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 ...
0
votes
2answers
190 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 ...
4
votes
2answers
618 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
votes
1answer
359 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
votes
2answers
451 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
votes
1answer
164 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[...
0
votes
0answers
45 views
Finding lossless coefficients to multi-tap feedback delayline
I have a digital delayline code which looks like this:
...
4
votes
1answer
668 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
votes
1answer
49 views
Books on delay / lag compensation
Which books do you recommend that provide comprehensive overview of delay compensation techniques in control systems?
1
vote
0answers
398 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 ...
