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
2 answers
31 views

Sampling of the DTFT causes the inverse transform to become periodic?

As you can see the above equation, DTFT is calculated from sample x[n] which is discrete sample of x(t). But calculated X(w) is continuous, even though it is calculated from discrete value of x[n] as ...
1 vote
0 answers
32 views

Single Kalman Filter: Resistance based on measurment of current and Voltage [closed]

Given measurement of voltage and current, which contain gaussian noise with known variance and a constant unknown offset $a_0$, I have attempted to estimate the resistance $R=\frac{V}{I}$. The ...
  • 41
0 votes
1 answer
50 views

Interpreting sensor noise data

Introduction :I am trying to create an EKF for an autonomous vehicle, and i need to model the error of the sensors. (I am a mechanical engineer so my knowledge on electric signals is limited). The ...
0 votes
1 answer
34 views

Strided unpadding energy relationship?

If x1 = x0[::2] is unaliased subsampling, then $E(x_1) = E(x_0)/2$, which can be proven via Parseval's theorem. For same $x_0, x_1$, however, ...
0 votes
1 answer
60 views

Average of discrete periodic signal

I am working on a project which, at some point, relies on the computation of the average of discrete signals, which typically look like this: The project generates hundreds of such signals, and: the ...
-1 votes
1 answer
118 views

Why is this Python implementation of trigonometric interpolation not working properly?

Consider a signal $u_j, j = 0, 1, \dots, N-1,$ sampled on an evenly-spaced grid of points, $x_j$. Define the discrete Fourier transform of $u_j$ by $$U_k := \frac{1}{\sqrt{N}} \sum_{j=0}^{N-1}u_je^{-(...
  • 3
0 votes
1 answer
88 views

Adding Fractional STO to an OFDM Signal using Frequency Domain Zero Padding

I have an OFDM system. I would like to introduce a fractional delay of (0.25 samples). Therefore: I increase the sampling rate of the OFDM signal by a factor of 4 (via frequency domain zero padding (...
0 votes
1 answer
38 views

Weird Pattern in the Power Spectrum diagram (i.e. the frequency domain of the signal)

I am quite a newbie to signal processing. I convert the time-domain signal to the frequency domain with the automated power-spectrum generator in the matlab app. The frequency domain has this ...
  • 1
0 votes
2 answers
73 views

Does Zero padding cause noise in the high frequency region?

I have an OFDM system. I would like to introduce a fractional delay of (0.2 samples). Therefore, I increase the sampling rate of the OFDM signal by a factor of 10 (via frequency domain zero padding), ...
0 votes
1 answer
177 views

Calculate the energy of x[n]

I'm trying to calculate the energy of this signal: x[n] = $(\frac{1}{2})^n\sin(\frac{\pi}{2}n).u[n] $ $$E = \sum_{n=-\infty}^{+\infty}\left|\left(\frac{1}{2}\right)^n \sin\left(\frac{\pi}{2}n\right) u[...
3 votes
2 answers
114 views

Applying a window to a signal

How can I Gaussian or Bartlett window to a signal? On the other hand, is it a good way of smoothing signals? If not what are the differences between smoothing and windowing?
0 votes
0 answers
30 views

n-dimentional integral over Multivariate Gaussian

given the prior distribution of $\mathbf{a}=[a_1,\ldots,a_K]^T$ as \begin{equation} p_{\mathbf{a}}(\mathbf{a})= \frac{1}{\pi^K \det{\mathbf{R_{\mathbf{a}}}}} e^{\mathbf{a}^H \mathbf{R}_{\mathbf{a}}^{-...
  • 135
0 votes
2 answers
76 views

When is the Fourier transform of a periodic discrete signal $\mathcal{F}x[k]$ the same as $x[k]$ up to a diagonal matrix

I am looking for all pairs $(x[n],q)$ where $x[n]$ is a periodic discrete signal with period $N$ and $q$ is a rational number satisfying the following identity: $$\mathcal{F}x[k]=e^{i(q-\frac{\pi k}{...
  • 267
0 votes
1 answer
139 views

Are there any order analysis functions in Python?

I would like to perform the following order related tasks in Python: Convert tachometer pulse signal to RPM signal (tachorpm) Convert RPM signal to even-angle signal (orderwaveform) Time synchronous ...
  • 133
0 votes
1 answer
49 views

Why do I need to shift time for getting a response?

Well this is a basic doubt. Let us take an example of a discrete time impulse response of a system as h[n] which has components at n= 0,1,2. Now my input signal is made of x[0]+x[1] I know the ...
2 votes
2 answers
92 views

Transformation of the independent variable of signals

I am struggling to understand the concept of transformation of the independent variable of signals. Let $x[n]$ be a DT time signal. As per my understanding, $x$ is a function of $n$, so it is not ...
0 votes
1 answer
55 views

calculate discrete time signal convolution example by hand

Conv. is defined this way:$y[n] = \sum_{i=0}^\infty h[i]*x[n-i]$ I have this example: $x[n] =(3,-1,2,0,1)$ at sample times $n= (0,1,2,3,4)$ is the input of an LTI system with impulse response $h[n] = (...
0 votes
0 answers
77 views

How can I generate long time series data of band limited gaussian white noise in Python?

...
0 votes
1 answer
38 views

Representing changing sample rate in block diagram and frequency response plot

I have an discrete integrator which sums over a block of input samples to produce output samples at a lower rate. The integrator sums a block of 8 input samples, multiplies the sum by a coefficient, ...
0 votes
1 answer
49 views

Find maximum of a square wave with variable frequency

I have an experimental signal (measure) that looks like a pwm signal: I want to find the x coordinate (time) of the maximum, i.e., the x coordinate where there is more density of the high values (255)...
0 votes
0 answers
48 views

how to convert continuous signals into discrete signals / signal power

I've just started learning about continuous and discrete signals. I don't really understand how to convert continuous signals into discrete signals especially since there are no values given.
  • 1
0 votes
1 answer
70 views

what the difference between spectral density and the power spectral density?

What is the difference between the spectral density and the power spectral density, Or they are the same thing? In fact, I find this term in the book of GODA 2000.
0 votes
1 answer
99 views

How to draw the PSD from a time series

I try to draw the spectral density of a time series in order to compare it with the theoretical one. Please can any one help me to do this. This is the time series of all the data. Thanks Dan Boschen ...
0 votes
2 answers
48 views

What is the difference between delay and difference properties of z-transform?

I'm working on a discrete updating algorithm as follows: $x[n+1]=Kx[n]$ Here $K$ is a constant. The continuous counterpart of this algorithm translates to: $\dot{x(t)}=Kx(t)$ While the Laplace ...
0 votes
0 answers
31 views

pan-tompkins algorithm for qrs detection

1- in pan-tompkins algorithm a bandpass filter of cuttoff frequency of 5hz-11hz was used , can i use a bandpass filter of 0.5hz-45hz instead with the same algorithm ? 2-why do we need moving window ...
  • 31
1 vote
2 answers
96 views

Reverse convolution

I was reading about linear systems and random processes and I came across this $$h_{k}*h_{-k}*rxx[k].$$ I know what convolution is and its formula. Does the minus sign affect both of the parameters in ...
  • 55
1 vote
0 answers
55 views

Why some implementation of Wavelet transform use reconstruction filter instead of decomposition filter?

I'm using MODWT (Maximal Overlap DWT) to extract features from a signal. Matlab implementation is using reconstruction filter instead of decomposition filter. In the first level of modwt decomposition,...
2 votes
1 answer
40 views

pan-tompkins algorithm

The difference equation of the differentiator used in pan-tompkins algorithm is as follows : ( a five-point derivative) $$ y \left( n T \right) = \frac{1}{8} T \left[-x \left(nT - 2 T \right) - 2x \...
  • 31
0 votes
1 answer
50 views

Multi-path equalization in SERDES system analysis

In transmitter I send the data 1 sample per bit, then received in Rx passing by ADC then FFE adaptive filter and then a slicer to return the samples in bits and calculate the BER and it works well ...
0 votes
1 answer
115 views

Spectrum of triangular pulse - MATLAB

I am new in matlab.I was given the code for spectrum of rectangular pulse of amplitude 1V and duration 1ms, and now I have to find the spectrum of a triangular pulse of amplitude 1V and duration 1ms ...
1 vote
2 answers
98 views

How to calculate frequency of a periodic signal?

I know there are similar topics but I can not find any solution in my situation. I have an accelerometer sensor and a basic microcontroller. Accelerometer data is collected in an array via i2C. I want ...
  • 21
-1 votes
1 answer
97 views

How to compute the inverse Z-transform

How to compute the inverse Z-transform of the form $$ G(z)=\frac{z^{2n}}{a(z^{2n})+b(z^n)+c} $$ I started by taking $$ F(z^n)=G(z) $$ so $$ \frac{F(z)}{z}=\frac{z}{az^2+bz+c}$$ This can be solved ...
0 votes
1 answer
165 views

Signal decomposition to even and odd components

I'm trying to decompose some signal to even and odd components, here's the Python code of it: ...
  • 95
0 votes
1 answer
17 views

Questionable results of on-line butterworth bandpass filtering using scipy.signal.lfilter

I have a data_stream that I'm attempting to filter using two on-line butterworth bandpass filters to extract two frequency bands of interest. The original ...
1 vote
0 answers
19 views

What is meant by discrete time plot with Whatsapp voice notes? [closed]

You might have noticed ,as shown highlighted in attached snap, whatsapp voice notes are bearing a discrete time plot Is it exactly referring to sampled(discrete time)version of waveform of actual ...
  • 931
0 votes
0 answers
27 views

Question in DSP signal flow graph

How to convert signal flow in Fig3 to Fig4? Is these two equivalent? ZHANG Xiuli, ZHANG Ruihua, CHEN Weidong. Design of digital parametric equalizer based on second-order function[C]// IEEE ...
0 votes
1 answer
54 views

Maximum possible CFO that can be estimated

I was trying to model the CFO (Carrier Frequency Offset) estimation in MATLAB. The Frame I was working on is of the following structure, yellow being the information data. How CFO was introduced? ...
  • 385
8 votes
1 answer
125 views

Clear understanding of compressed sensing

I am trying to get a clear understanding of how compressed sensing works. A continuous signal $x(t)$ is under-sampled (less samples are collected than the numbers required by the Nyquist theorem). The ...
0 votes
0 answers
82 views

How to get epochs from eeg data in python?

I am working on sleep stage classification and have EEG data from the link : https://physionet.org/content/hmc-sleep-staging/1.1/ I am using pyedflib to extract the data. I am tring to extract the ...
0 votes
0 answers
27 views

Why does the variance of the Empirical Transfer Function Estimate not decay with increased sample points?

Please refer to Ljung's Lemma 6.1. In short, this lemma tells us that for a given LTI system $y[n]=g[n]*u[n]+v[n]$ where $v[n]$ is a stationary stochastic process with a zero-mean and a finite power ...
  • 129
0 votes
0 answers
14 views

Getting the detail coefficients as feature vectors

I am trying to get feature vectors from the coefficients I have generated. The spectra are decomposed using 8 levels and I am only choosing the coefficients of ...
0 votes
2 answers
30 views

Discrete signals - Z Transforms

If a system has transfer function $H(z) = 1 + z^{–1} + z^{–2}$, then for an input signal of the sequence = {1,2,3,1,4,-2, 4} calculate the output sequence of the system. DO i put transfer function ...
  • 1
1 vote
1 answer
93 views

Finding the impulse response of $y[n]=\tfrac12y[n-1]-\tfrac15y[n-2]+x[n]$

I'm new to signals processing and up until now we'd assume that $x[n]$ is the input and $y[n]$ is the output, and when I wanted to get the impulse response I'd simply replace $x[n]$ with sigma and $y[...
0 votes
1 answer
44 views

reconstruct the low resolution signal before upsampling

When we upsampling a discrete 1d signal by 2x, we first interleave the signal by 0 and add zero padding, then pass through a low pass filter. low resolution signal [x1, x2, x3, x4] -> interleave 0 ...
  • 103
3 votes
1 answer
52 views

Sufficient condition for a system to have memory

This is for a black box system which is not LTI and for which we have no input output expression, but we have some examples of sample inputs and corresponding outputs. I believe in this situation, we ...
1 vote
1 answer
23 views

How to find the relative energies between multiple frequency bands?

I am filtering my input into four frequency bands using IIR filters. The output of each band has some disturbances or ripples in it. I am looking for a method to normalize the four bands so that all ...
1 vote
1 answer
69 views

Signal to noise ratio for time series audio data

I am writing some software to benchmark an audio noise filtering method using SNR as an evaluation metric. One software component generates noisey audio by taking a clean audio file and a noise source ...
5 votes
3 answers
806 views

A case that zero padding increase real resolution and extract more info than naive DFT?

It is widely accepted that zero padding cannot reconstruct more information that is originally present in the sample data, which I think is intuitive, because zero padding adds no more information. ...
0 votes
1 answer
24 views

Does different frequency signal cause different voltage from antenna?

When antenna received signal,antenna generate voltage,then SDR convert voltage to I=amplitude*cos(t)and I=amplitude*sin(t). When ...
  • 175
5 votes
1 answer
342 views

The Matrix Form of a 2D Circular Convolution

I have 3 closely related questions regarding 2d convolutions and how they are represented in matrix form. 1. Miming what happens in 1d, I assume the product of a doubly block circulant matrix $A$ by a ...
  • 53

1
2
3 4 5
45