Questions tagged [discrete-signals]

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

Filter by
Sorted by
Tagged with
0
votes
1answer
20 views

Can we apply CZT after FFT?

I want to improve the frequency resolution of the FFT algorithm. Can CZT (Chirp z transform) be better to use after FFT. Because i read in some articles that CZT has better frequency resolution than ...
2
votes
1answer
48 views

Hankel Matrix SVD Denoising

I have performed Hankel Matrix Singular Value Decomposition de-noising to smooth out my univariate time series. It is the close price of EUR/USD exchange rate. Here is a picture: The problem I have is ...
0
votes
0answers
36 views

Frequencies calculation of discrete signal in frequency domain

I have some misunderstanding in definition of frequency resolution of the signal. Here it is assumed that the resolution is: $$\hat{f_k}=f_{signal}\cdot T_{sampling}$$ (which is just relation of ...
0
votes
0answers
17 views

How can I generate X Axis componant in R_xy in MATLAB?

Let's say I have cross-correlated $x(n)$ and $y(n)$ and got the $R_{xy}(n)$. Now if I want to generate the x-axis component of $R_{xy}(n)$ in the command window of MATLAB. How can I do that? is there ...
0
votes
0answers
15 views

Fourier transform of x[n] = e^(jn/8)*u[n]? [closed]

Fourier transform of x[n] = e^(jn/8) is non-zero for only w=w0, w0=1/8 here. It is an impulse at w=w0. But what is the Fourier transform of x[n] = e^(jn/8)*u[n] ? I couldn't find out.
2
votes
2answers
68 views

zero-centered and causal zero padding

I have followed the link below to simulate two different zero-padding methods (zero-centered and causal) https://ccrma.stanford.edu/~jos/mdft/Zero_Padding.html Sample code ...
0
votes
2answers
48 views

How would one solve this question if no initial conditions are given? Which assumption can I make?

This was a question on our test, I know it can be easily solved by Z-transforms but there are no initial conditions specified. In this case, what would be the right approach? Assume all initial ...
0
votes
0answers
12 views

How can we divide our long-time domain signal into equal segments and then apply Wavelet transform?

I have a time-domain signal and the samples size is 80000. I want to divide these samples into equal sizes of segments and want to apply wavelet transform to them. How I can do this step. please guide ...
1
vote
1answer
52 views

Causal inverse of $h[n]=\delta[n]-\alpha\delta[n-1]$

Find the causal inverse of $$h[n]=\delta[n]-\alpha\delta[n-1]$$ we have $h[0]=1$ and $h[1]=-\alpha$ also $h[n]=0$ for $n>1$ From the formula $$ h_i[n]=\sum_{i=1}^n\frac{h[n]h_i[n-i]}{h[0]} $$ we ...
0
votes
1answer
74 views

Implementing basic high pass filter using difference equation

For the following signal, I am trying to remove the gradual positive drift but retain the spikes using a high pass filter. I am aware that I can use implement a high pass filter using difference ...
1
vote
1answer
63 views

Help understanding quadrature sampling and effective bandwidth

Let me start off by saying I'm at least a little embarrassed that there's something simple that I'm fundamentally not understanding here. Not sure if the blame is on me, or the prof that taught me DSP ...
2
votes
1answer
78 views

Combination of type I FIR linear-phase systems

Let $h_1[n]$ and $h_2[n]$ be impulse responses of type I FIR linear-phase systems with lengths $M$ and $N$. What can be said about the phase response of the following filters? $h_3[n] = h_1[n] + h_2[...
0
votes
0answers
17 views

Where is SNR and CNR calculated for LTE?

I read below that SNR and CNR are different and we have difference of post/pre modulation. In context of LTE which modulation do we refer to- Digital Data modulated using QAM/QPSK to IQ, or Baseband ...
0
votes
1answer
47 views

How to detect a long deceleration phase in a signal?

Given the following signal, I would like to keep only the deceleration phase in orange. I have no idea whether there exists techniques to do that or not. I imagine that I can smooth the signal, ...
1
vote
2answers
86 views

How to interpret values of the autocorrelation sequence?

I know that (auto)correlation indicates the "degree of predictability" of a variable with respect of another. However, this is a vague notion. I know that a blank process should have an ...
0
votes
0answers
22 views

How to find segment with specific speed on the signal in comparison with reference signal?

How do I find a segment on the signal where the signal speed is 2 times the speed of the same segment on a reference signal? Which features describe this? On attached image can see "change of ...
0
votes
1answer
71 views

Phase plot from impulse response function does not match that of the frequency response function

I have a first order linear filter $$ H(s) = \frac{1}{1+\tau\,s} $$ With the impulse response function, found using the inverse Laplace transform as $$ h(t) = \frac{1}{\tau}\,\exp\left({-\frac{t}{\tau}...
0
votes
1answer
37 views

Causality on an accumulator system

Can anybody explain why is this system not causal. $$T[x[n]] = \sum_{k=n_0}^{n} x[k]$$ How does it depend from future inputs when $n < n_0$. If $n < n_0$ then $T[x[n]]$ is zero because of ...
0
votes
1answer
60 views

Is there an order to apply time shifting and frequency shifting to signals in DTFT?

For instance in one question applying frequency shifting first and then applying time shifting yields a different answer wrt applying time shifting first. Please elaborate i am clueless. if i use ...
0
votes
1answer
48 views

How to choose the roots of 4 different Zadoff-Chu sequences? [closed]

I would like to generate 4 Zadoff-Chu sequences. The sequence length is 63. I need to properly choose the roots (r1, r2, r3, and r4) so that: Each root is relatively prime to the sequence length ...
1
vote
1answer
50 views

Expression of output for discrete time causal filters

I have a question about the expression of the output of a discrete time filter described by its impulse response $h(k)$. Looking at the defintion of a discrete filter with input $u(k)$ and output $y(k)...
4
votes
2answers
91 views

Biexponential (double exponential) convolution of a function

Summary I am trying to run a convolution on some data that was originally calculated from a deconvolution (so the reverse). However I'm not getting the expected graph. Blue is expected, red is a ...
2
votes
1answer
81 views

How could I do a Discrete Fourier Transform in Python if my data is non uniform?

I have been trying to find a way to transform my time series data in an equivalent manner to the discrete Fourier transform. What I wish to find is something like: ...
1
vote
0answers
63 views

Why is voice clipping happening after Dynamic Range Compressor (MATLAB) when applied in real time on chunks of data?

I have been working on real-time audio signals on smartphones (iOS and Android) and my goal is to make voice amplitude stable in a certain range even if a person is talking closer to the mic of the ...
0
votes
0answers
16 views

Inverse DCT4 by using Inverse DFT

Say I have an inverse DFT function ready for use. I am struggling to find online or mathematically deduce the additional steps needed to compute an inverse DCT4 by using said inverse DFT function. If ...
0
votes
2answers
94 views

Pulse-shaping FIR filter

I understand that pulse-shaping is performed to limit the bandwidth of the transmitted signal, but I would like to know how pulse-shaping can be implemented using an FIR filter.
0
votes
1answer
36 views

Convolution of a discrete continuous function for reconstruction

From chapter 9 page 198 of https://github.com/t4world/Computer-Graphics/blob/master/Fundamentals-of-Computer-Graphics-Fourth-Edition.pdf I am confused as to what this book's description is saying ...
2
votes
2answers
309 views

Is it possible to calculate a 48-point FFT using a 32-point FFT and 16-point FFT?

I have to calculate a 48 point FFT using an N-point FFT library function which only supports lengths that are a power of 2. Is it possible to calculate a 48-point FFT using a 32-point FFT and 16-point ...
0
votes
1answer
21 views

Mapping a shifted and sequence to a given output axis

I have a sequence x1, which is the same length of an output vector (nx). However, the output vector goes from -12890:13975. I need to define the output (y[n]) of the system along the axis (nx). I ...
0
votes
1answer
23 views

Defining a discrete sequence along an arbitrary time axis

I need to compute the output of the system y[n] = x[−n]. x[n] is of length 1 : 26866, and the y[n] output axis has the same length and goes from -12850 : 13975. variables: x[n] = x1, output axis y[n] ...
0
votes
1answer
43 views

converting complex sum of exponential signal to real signal

I have the following Signal model, that generates a discrete-time complex signal, where $a_k$ - amplitudes, $\phi_k$ - phases, $\alpha_k$ - damping factors and $f_k$ - frequencies are the parameters ...
4
votes
1answer
74 views

How to linearize this state space model and write it in discrete form?

This might not be trivial nor short so in advance thank you all who read this in attempt to help. I'm building a Kalman filter in matlab and I'm fairly certain the software itself is working correctly ...
0
votes
2answers
35 views

Is this system time-invariant?

I have this system: $$y[k] = (1 + (-1)^k)x[k]$$ I would like to know if it is time-invariant or not. I've done some work and came out with this: $$y_1[k] = (1 + (-1)^k)x[k - k_0] = y_2[k] = (1 + (-1)^{...
0
votes
2answers
81 views

What does it mean to calculate the FFT of an integer sequence?

The Fourier transform is used to map functions to and from time/frequency domains. I can make sense of what it means to calculate the Fourier transform of, say: $$y(t) = e^{j\omega_0t}$$ which is $$Y(\...
0
votes
1answer
56 views

State-space model and/or TF for a $K$-th order linear system given the signal sequence

The discrete-time signal $x_n$ is a sum of $K$ discrete-time complex damped exponential: \begin{equation} x_n = \sum_{k=1}^{K} \underbrace{(a_k e^{j\phi_k})}_{c_k} {\underbrace{e^{\{(- \...
0
votes
1answer
54 views

Sum of complex exponential signal in MATLAB

I want to create a sum of damped complex exponential signal with the known values of frequency $f$, damping $\alpha$, amplitude $a$ and phase $\phi$ for the $k = 1,2,...,K$ exponentials. Is there ...
11
votes
6answers
836 views

Do discrete-time series always have a continuous-time underlying?

Can one argue that discrete time-series coming from stocks or commodities (prices) are derived from a continuous-time process? One can probably argue that stocks or commodities at any time have a ...
0
votes
1answer
25 views

$H(e^{j\omega})$ represented with a limited no of samples

I have a low pass filter defined as: $$ H_{lp}(e^{j\omega})=\left\{ \begin{aligned} &1 &|\omega|>\omega_c \\ &0 &\omega_c<|\omega|<\pi \end{aligned} \right. $$ and the ...
4
votes
1answer
74 views

Kay Statistical Signal Processing Estimation Theory Example 7.14

Example 7.14 from Kay Estimation Theory A common WSS random process has the ACF $$r_{xx}[k]= \begin{cases} 1+b[1]^{2}+b[2]^{2} & \text{k = 0}\\ b[1] +b[1]b[2] & \text{k=1}\\ ...
0
votes
1answer
43 views

How to remove or smooth the comb filter effect in real time audio signal mixing?

I have been working on a project where I have to mix multiple audio signals of the same source coming from different slave smartphones on one master smartphone in a distributed way. Now I have aligned ...
0
votes
1answer
16 views

How to rectify acceleration vibration signal?

I have acceleration vibration signal containing 2500 data points. What I need to do is rectifying the signal becomes no negative values but still has same mean and standard deviation as the original ...
0
votes
0answers
9 views

Efficient Method to match vector time series where the vector entries may not line up

Asking here because I couldn’t find or didn’t have the right words to search for the answers online. Also sorry for no examples—gotta maintain my NDA for work. I have two N-dimensional vector time ...
8
votes
3answers
565 views

What is the definition of a "Symbol"

I’m looking for the simplest, precise definition of a Symbol e.g. The symbols found within a signal The signal has a N symbols per second I'm following this tutorial. The fellow defines the term ...
1
vote
2answers
79 views

Encode bits in timing of signal

If you had two computers with two atomic clocks you could measure the time between signals at $10^{-16}\,\text{s}$. Can the time between signal pulses be used to encode additional bits of information ...
0
votes
1answer
95 views

Periodic signal detection algorithms?

I am currently working on pulsar signal periodicity detection. Most of the literature which i studied used traditional FFT (Fast Fourier Transform) or (Epoch Folding) techniques to find the ...
1
vote
1answer
67 views

Prove Convolution Property for DFT using duality

If $x_1[n]$ and $x_2[n]$ are finite length sequences of length $N$ $$\mathcal{DFT}(x_1[n] \circledast x_2[n]) = X_1[k]X_2[k]$$ where $X_1[k]$ and $X_2[k]$ are the DFTs of$x_1[n]$ and $x_2[n]$, ...
0
votes
1answer
56 views

Prove Discrete Time Fourier Series Multiplication property

Note: This is not a homework problem. I'm just stalled at a point because I think I might be interpreting the duality property incorrectly. If $x_1[n]$ and $x_2[n]$ are periodic with period N, then if ...
0
votes
0answers
31 views

How to effectively stationarise non-periodic wave signals?

I am pre-processing a non-periodic signal for further implementation of autoregressive modelling on the signal. The signal is shown in the following figure. However, when I applied the Augmented ...
0
votes
2answers
73 views

Design of all pass filter with desired phase response

I want to design an all pass filter with a desired phase response in MATLAB. But in MATLAB, all pass filters are designed either by specifying the all pass filter coefficients or from a transfer ...
0
votes
1answer
32 views

n independent, normal, random variable distribution

There is 2 time-series signal and we have to compare the distribution of them. I have heard there is a theory that says for n independent, normal, random variables of a series with many members, the ...

1
2 3 4 5
43