Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [discrete-signals]

A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities.

0
votes
0answers
35 views

Interpreting Auto correlation results

I used xcorr function in Matlab to compute the autocorrelation of my signal. I obtained a graph, which is shown below. How to interpret this? I read that autocorrelation helps in finding the patterns ...
0
votes
0answers
36 views

How to low pass very few samples

I'm asking myself what is the best way to low pass a signal which only has a few hundred samples? Or is there a proper way at all? It must not be a sound signal but I used Audacity to display the ...
0
votes
0answers
44 views

Region of convergence for discrete system

I am confused by two questions on the region of convergence (ROC) when applying the $Z$-transform. Consider a discrete-time linear system $$x[n+1] = Ax[n]+Bu[n], \qquad y[n]=Cx[n]+D$$ whose transfer ...
0
votes
1answer
53 views

How to determine the filter type based on the impulse response?

When given a discrete impulse response, let us say it is from an FIR filter so it is finite, how can I assume the filter type? The task is to recognize or to preclude one or more of the following ...
0
votes
1answer
34 views

Reason of effect of continuity and discreteness on periodicity of signal?

We know that a sine signal in continuous time is a periodic signal with a period $2\pi$ whereas the same sine signal in discrete time is aperiodic. My question is how changing just a type of signal (...
0
votes
1answer
39 views

About the variance of the coefficient of narrowband noise when using signal-space representation

Assume that n(t) is a white Gaussian noise process with zero-mean and power spectrum density $N_0/2$. By using the signal-space representation, it can be expressed as: $$n(t) =\sum_{j=1}^N n_j \...
1
vote
2answers
45 views

Energy of a signal

Suppose that $E(k)$ be the energy distribution of a signal in spectral domain with a finite total energy. Is there anyway to concentrates all the energy of signal around a specific point?
0
votes
1answer
32 views

Is there a name for the result of summing the bins of an FFT?

Is there a name for the result of summing the bins of a DFT? I don't mean to sum the squares of the bins, but to simply add the magnitude of the frequency bins together to get a single result. Is ...
0
votes
0answers
16 views

How can we do finite-step signal sampling in practical?

The signal has infinite length. We cannot sample it with a whole length. How can we truncate a infinite signal and sample it in finite step? And then how can we analyze it.
0
votes
0answers
87 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
0answers
27 views

Problem with Spectral Correlation Function for cyclical signal analisis

I am using the autofam() function in Matlab for the Spectral Correlation Function (link: https://github.com/sayguh/MastersProject/blob/master/matlab/sandbox/autofam.m) for a BPSK modultated chirp ...
0
votes
1answer
63 views

How to get a heartbeat signal from this data?

I am giving my first steps in data analysis, gathering/cleaning. To learn, I am trying to create a simple code that can detect heartbeats from color variations from the image coming from the camera ...
1
vote
1answer
46 views

Nyquist frequency , sampling distance

I have few questions I tried to solve regarding nyquist theorem, and I would like to see your opinion if I'm doing it correctly?(one I know the answer second one not sure). 1.Let $f(x)$ and $g(x)$ be ...
1
vote
1answer
60 views

Equivalence of ML and DFT Peak Finding for Single Tone Estimation

My understanding is Maximum Likelihood and DFT Peak Finding for a single tone produce the same results assuming the ML is restricted to the same frequencies as the DFT. I was wondering if there was ...
0
votes
2answers
99 views

Algorithms for detecting the difference between two signals

If I have two signals $X$ and $Y$, where $X$ is a clean signal and $Y$ is the same signal with linear white Gaussian noise and an amplitudes of $10^{-4}$. How could one use an algorithm to detect if ...
1
vote
2answers
70 views

Nyquist sampling

I know that if $f_\mathrm{m}$ is the "Nyquist frequency" (max frequency) and $f_\mathrm{s}$ sampling rate then $f_\mathrm{s}>2f_\mathrm{m}$. Am I correct so far? I have a signal $x(t)$ with max ...
1
vote
2answers
90 views

Proof that first difference filter amplifies noise

I'm a bit befuddled by noise's effect on derivative filters. I've always 'known' that straightforward first difference derivative filters of discrete signals amplifies noise, but I'm struggling to ...
1
vote
0answers
33 views

Band Edge Filters

I am interested in using Band Edge Filters to do carrier frequency recovery but this is kind of secondary to my question which is: How do you build an FIR filter which isn't symmetric about the ...
1
vote
1answer
38 views

Difference between autocorrelations

M. H. Hayes calls in his book "Statistical digital signal processing" autocorrelation sequences $r[k]$. For optimal filters the desired autocorrelation has the index d -> $r_d[k]$. However, often ...
3
votes
1answer
51 views

Potential issues arising from too stable discretization

When numerically simulating a system, usually some kind of discretization is necessary, obtained by some kind of z-transform, such as, for instance, the bilinear transform $s\mapsto \frac{2}{\triangle ...
0
votes
2answers
43 views

Correlation between 2 signals of uneven dimensions

As a part of my work, I am trying to correlate the audio signal in a video with the pixels of each frame. The steps I follow are: Audio sampling rate and frame rate of the video are known. So, ...
1
vote
0answers
24 views

Why is my resampled signal cutoff when resampling with a windowed FIR filter in MATLAB?

I have an exercise to write a function which upsamples or downsamples a signal by a factor of F (integer) using a FIR filter windowed with a Kaiser window function. Exercise I had last week included ...
0
votes
0answers
24 views

Why are patterns repeated in the frequency-power graph of a periodic signal?

The original question was posted here. I have a signal, which I'd like to treat as a non-continuous function now, let it be $signal(t)$. It looks like this: Zoomed in a bit: I create a Lomb-Scargle ...
0
votes
1answer
53 views

Active Noise cancellation for non periodic signals

I observed that the coded algorithm for active noise cancellation is not able to cancel some of the signals like a human voice. Is there any solution for this? Can we really cancel non-periodic ...
0
votes
1answer
36 views

periodicity of constant discrete time signals

are constant discrete time signals periodic? example \begin{equation} e^{i10\pi n} \end{equation} my proffesor says that this signal is aperiodic, in the discrete sense. but it seems wrong, because ...
2
votes
1answer
30 views

Error due to downsampling an image

I have two images $I_1$ and $I_2$ suppose $I_2 = downscale(I_1)$, so for example if $I_1$ has resolution 1024x1024 $I_2$ could be 512x512. How can I measure how much quality I've lost during this ...
0
votes
0answers
9 views

Correct way to calibrate RX into a measuring receiver

While playing with my SDR (Software Defined Radio) Board, I was interested in performing a TX output power table at different center frequencies and TX antenna gains. I have an RF frequency generator....
0
votes
0answers
41 views

Power Spectral Density of discrete White Gaussian Noise defined with variance and sampling interval

From Creighton and Anderson Chapter 7 on Gravitational Wave data analysis: Please explain where the delta t and the limit came from in this derivation.
0
votes
1answer
31 views

how is this method of proving shift invariance correct

I got this answer from here. But i don't know how this method is correct. Until now to prove shift invariance what i did was : step 1: delay output and write it in terms of input. step 2: delay input ...
1
vote
1answer
81 views

Can Temperature data be predicted using adaptive filter using LMS algorithm?

I am working on a project which requires me to implement adaptive filter as a predictor. I have just started on adaptive filter and I intend to use least mean square algorithm for weight adjustment. ...
0
votes
1answer
24 views

What's wrong with this Whittaker-Shannon-Kotel’nikov interpolation implementation?

I tried to implement Whittaker-Shannon-Kotel’nikov interpolation formula but I get unexpected results: the reconstructed signal lags with respect to the original. I know that I can not expect a ...
2
votes
2answers
85 views

Signals - question due to sampling

I don't have an idea how to start it. Help pls :) $$m = z(t) + \frac{\operatorname{Sa}(t-T)}{4}$$ We have some signal $z(t)=\left(\operatorname{Sa}(\frac{t}{T})\right)^2$. How often the m signal ...
1
vote
3answers
380 views

Measure Sine Wave Amplitude from ADC Signal

Question I'm trying to do some DSP that I have never done before and a nudge into the right direction would come in handy. The context is replication of this project. The system architecture is the ...
0
votes
1answer
38 views

Sampling - Higher order harmonics

I have been studying about the sampling theorem and it seems that even though we sample at a frequency with the nyquist criterion, the harmonics (due to sampling process) remain within the nyquist ...
0
votes
1answer
98 views

Difference between the DTFT and DFT [duplicate]

I know this question has been asked before. It is, however, so confusing, that I'd like to give this another try: I have come across the following 2 definitions of the DTFT: So, the first line is the ...
0
votes
0answers
35 views

How to make function in time domain after fft fit with the corresponding function in frequency domain?

For example, I want to use fft to transform the simple function exp(-x.^2) defined in time domain. And the corresponding funciton in frequency domain is sqrt(pi).*exp(-k.^2/4). And I use the upper ...
0
votes
0answers
17 views

How does discrete spectral moment relate to continuous spectral moment?

It is said in discrete/digital signal processing that $r$th spectral moment of signal $x[n]$ is defined as: $$\sum_{n=-\infty}^{\infty}n^r x[n]$$ But how does this relate to usual continuous $r$th ...
0
votes
0answers
60 views

Use 2D FFT to replace 2D Discrete Fourier Transform (MATLAB)

I met a problem. I ran a code to implement the 2D discrete Fourier Transform, here is the code: ...
-1
votes
1answer
30 views

integral filter

Assume we have a time domain signal: s(i), i=1:N. To apply a derivative filter to it, i.e. D*s, where ...
0
votes
0answers
27 views

Adaptive frequency discovery of binary signal

First of all, I'm not a signal processing expert. Actually, I'm trying to benefit from some concepts of signal processing theory in my computer science research. My problem is that, I have to find ...
0
votes
1answer
48 views

Distortion in sound after multiplying frequency spectrum by constant

I make a simple sound equalizer that operates in frequency domain and lets user to adjust frequencies in sound by using 4 sliders. The first one responsible for 0 - 5kHz, the fourth one for 15-20kHz. ...
0
votes
2answers
107 views

Higher order harmonics during sampling

I am studying about the sampling theorem in conjunction for ADC. I got little confused while reading about aliased frequencies. I see that as per the Nyquist theorem, the sampling frequency (fs) ...
0
votes
0answers
27 views

Convolution with rectangular function

I have a system $h(t)=4e^{-4(t-4)}u(t-4)$ and I want to response of the system to $x(t)=rect(2(t+4))$. I have followed those steps: $y(t)=x(t){*}h(t)$ $=rect(2(t+4)){*}4e^{-4(t-4)}u(t-4)$ $=4[u(t)-...
0
votes
1answer
136 views

Compute time constant of discrete exponential decay pulses

I want to retrieve (within a FPGA) the time constant $\tau$ of incoming pulses of the form $$x[n]=Ae^{-n/\tau}u[n]+C$$ In addition to the offset, inputs are subject to noise. To measure the integral ...
0
votes
0answers
15 views

Signals time fluctuation

I am following this paper. I am lost in equation 3. What exactly is a signal's fluctuation? What does the $\delta$ here represents? Also why does it's autocorrelation is represented as $\langle \...
0
votes
0answers
25 views

Removing outlier data points from frequency-domain signal

Hello signal processing stack exchange, I have a complex frequency-domain signal representing the impulse response of a physical system over some range of frequency space. As an artifact of the ...
0
votes
1answer
38 views

Very basic question about filters in signal reconstruction

I am studying digital signal processing and I would like to ask a question about sampled signal -> original signal reconstruction filters. Most textbooks use a box filter or a tent filter to show how ...
0
votes
1answer
36 views

Impulse response of a system from the input-output relation

I need to find out the recurrence relation and the impulse response of the following system. The relation seems to be $$y[n] = \frac{2}{16} x[n] + \frac{3}{16} x[n-1] + \frac{6}{16} x[n-2] + \frac{3}{...
0
votes
2answers
103 views

Linear Combination of Two Signals

In my signal processing class I have some basic tasks working with sinus signals in Matlab. I have two sinusoidal signals with 1kHz and 3kHz and sampling rate of 16kHz. The next task says 'Create a ...
0
votes
1answer
45 views

Cramér-Rao lower bound

I have been trying to implement the Cramér-Rao lower bound from the paper - A reference-free time difference of arrival source localization using a passive sensor array (eq. 6 and eq. 7). $$ \...