Questions tagged [time-domain]

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2answers
17 views

Is there a way to use decimation or linear interpolation to shrink or stretch an audio signal in the time domain?

I am able to shrink/stretch an audio signal using Python code for a phase vocoder, as well as the stretchAudio function from Matlab's Audio Toolbox. Although both methods do indeed alter the audio ...
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0answers
14 views

Is Kaiser-Bessel filter good for notch filtering with time-sensitive data?

I'm working with ECG signal processing and want to implement digital notch filter. Would Kaiser-Bessel filter be optimal for signals sensitive to time domain disruptions or should I use different ...
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1answer
39 views

Time domain representation of a modulated signal when symbol rate >> carrier frequency?

I need to understand the relationship between carrier vs. bits with PSK modulation, and what the signal in the time domain would look like if my symbol rate is far greater than my carrier frequency. ...
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1answer
59 views

Any guidance on converting Time Domain to Frequency Domain in Matlab

Below is the graph of my load cell readings at 3 samples per second. I have collected 500 such samples. I want to stabilize the readings and read that first approach is to convert time domain data to ...
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1answer
271 views

What is wrong with my residue partial expansion method? (Transfer Function into State-Space Modal/Diagonal Form)

I'm using reference from here and here. This is Laplace transfer function of DC Control Speed System: $$\frac{\omega(s)}{V(s)}=\frac{K}{(Js+b)(Ls+R)+K^2}$$ Where, $\omega$ is the motor angular ...
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1answer
14 views

I am looking for an analytic description of a continuous-time Butteworth High-pass filter in the time domain (=impulse response)

having derived the Butterworth Lowpass Time domain response, I am now struggling to find a similar function for a Butterworth Highpass filter. I understand you need to replace s by 1/s. But this leads ...
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4answers
1k views

Butterworth filter transfer function in time domain

Preliminaries I need to know the response of Butterworth filter in time domain of the following input (at least numerically): $$ x(t) = \theta(t)(1-\exp\{-at\})\exp\{-bt\}, \quad a,b>0,\quad a\gg b ...
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1answer
189 views

How do audiobook players manage to quickly speedup/slowdown playback speed without using more memory?

Many audiobook player apps on Android have a reading speed slider which lets us choose the reading speed e.g. 0.5x 0.75x 1.00x 1.25x 1.50x. This is time-stretching ...
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1answer
46 views

Generating a time domain signal using the fundamental frequencies

I currently have the power spectrum (in dB) of a signal through which I obtained the fundamental frequencies and amplitudes. My question is: how to generate a time domain signal using these amplitudes ...
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1answer
39 views

Meaning of the frequencies vector using fft

I'm so confused, and it would be nice if someone could clear my head, or at least direct me to suitable references. Assume that I have two gaussian pulses with the same bandwidth in time, but for 2 ...
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1answer
22 views

Derive Time-Domain Biquad Coefficients from Z-Domain

I'm trying to derive the time-domain coefficients of a biquad filter based on its z-domain coefficients. The purpose is to import externally-generated EQ filters (in z-domain) into Max/MSP (in time-...
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1answer
94 views

Representing a positive 0-limiting continuous time domain function, in terms of spectral samples, outside of a window

Bit of an odd question Assume you have a known function $x(t)$ which is continuous, but approaches but is not equal to, 0, on the interval $[-\infty,\infty]$ . You know also that it approaches 0 ...
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1answer
281 views

Is it right to talk about dynamic range on frequency domain?

I'm comparing three frequency response's plots from simulations and experiments and I observed that two of them look like clamped to a DC component, where the max dB value is i.e. 100 and the min is ...
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0answers
59 views

Rectangular Pulse Train and Sinc Function

I wanted to ask that in frequency domain the rectangular pulse is a sinc function, so is this sinc function periodic or aperiodic? Also if signals that are continuous in time domain then they are ...
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1answer
21 views

Third octave band zero-phase forwards-backwards Butterworth filter adds amplitude to complex signals?

Overall aim: to take a short signal (likely to be noisy with some tonal components) and filter it into third-octave bands (TOBs), apply frequency-dependent spectral adjustments, then recombine the ...
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4answers
2k views

Time synchronous averaging - MATLAB

I have a time domain signal that corresponds to a vibration signal of a machine. I have a second signal that corresponds to a tachometer signal (There is a pulse every one revolution of the shaft). I'...
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0answers
34 views

Determining the right order of time-domain low pass filter for desired cutoff frequency

I've been stuck on a problem regarding complex demodulation of a signal for a while and wondered if anyone could help. Suppose I have a signal $X(t)$ such that \begin{align} X(t) &= A(t)\cos(\...
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1answer
55 views

How to calculate DTFT of cosine function divided by n

I'm having a hard time to calculate the next function, and I don't really know Matlab good enough to calculate it there. Help would be appreciated: $$h[n]=\frac{A_1 \cos⁡[\theta_1(n-N/2)]}{n-N/2}$$
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1answer
48 views

Time domain analysis vs frequency domain analysis? Applications wise? [closed]

When do we use time domain analysis and when do we use frequency domain analysis? As far i studied i know that when we need to study individual sinusoidal components of a signal, we choose frequency ...
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1answer
102 views

A one-pole LPF (6 dB/oct) has a step response to $1/e$ amplitude of ${\tt time} = 1/(2 \pi f)$. What would the response time be of a 3 dB/oct filter?

I was instructed in another question here that if a one pole (6 dB/oct) low pass filter is fed a discontinuity (ie. going from 1 to 0) it will take ${\tt time} = \frac{1}{2\pi f}$ to reach $1/e$ ...
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1answer
43 views

Are there any recursive online max/min filters for time-series

Are there any online recursive filters that can approximate local, time-varying minimum and maximum values of a time series?
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38 views

Is a LTI system with dead-time equivalent with a LTI system with no dead-time but delayed input signal?

I wonder if the system parameters would remain the same after all. According to the definitions, the gain is the change of the output induced by the change of the input if we assume that the gain is ...
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2answers
111 views

Questions about autocorrelation, correlation, and randomness

I'm learning about autocorrelation functions and trying to calculate some from a time series. Conceptually, what is the difference between the following two autocorrelation functions? $$g_{1}(\tau)=\...
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0answers
122 views

How to approach Feature Extraction and Feature Selection part in machone learning in python?

I am a bit new to machine learning and I have the following questions: Question 1: When dealing with feature extraction with signals from sensors, what is the typical approach to extract features ...
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83 views

Time domain to angular domain approach

I have a rotating shaft where I need to move from the time domain to the angular domain to look for vibration faults. I have the data from a tachometer. From another post I found these steps: The ...
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2answers
2k views

Extracting Peak Frequencies Using FFT vs. Time Domain Peak Finding

I am trying to compare two processing algorithms that I believe should be producing very similar results. I am processing acceleration signals over the course of the day and we expect to see a ...
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1answer
30 views

Time and Frequency Domain Relationship

Why do we say that a good time response means a bad frequency response?
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0answers
122 views

Frequency and Order maps

I'm new to python and I'm using it to analyse accelerations from an accelerometer ie. vibration analysis. For that I need to plot 2 types of diagrams: 1) Frequency map; frequency and time on the axis ...
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0answers
50 views

Time Frequency bin

I am doing research in audio signal processing for DOA estimation. I came across the term Time-Frequency bin. I have gone through several articles but none of them specify a TF bin rather it specifies ...
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3answers
625 views

How to filter out everything but a single frequency in the time domain?

I'm new to signal processing and would like some insights about the best way to filter simple data without being too computationally intensive. I have an audio signal and I want to extract a single ...
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1answer
79 views

Complex time domain signals and QAM

Is there an inherent connection between complex time domain signals and QAM? Given a complex time-domain signal is it always implied that this is a QAM-demodulated form of a real time domain signal? ...
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1answer
104 views

Pixel Wise Write into a Video File in MATLAB

A video file (in .ptw format) is read in MATLAB in the form of a 3 dimensional matrix (a structured format). My aim is to process the video in time domain on each coordinate pixel individually and ...
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2answers
78 views

Sampling Theorem: T-Sampled Signal

I am stuck in a small question which I am trying to solve. The signal $f$ defined by $f(t) := \text{sinc}(t)$ is to be sampled. How should I draw the illustrations of the $T$-sampled signal $f_{T} = (...
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1answer
78 views

Converting a discrete real time domain to a discrete complex time domain signal

To test my understanding of amplitude modulation in the frequency domain I'm trying to replicate the center frequency with 2 side-bands in an Octave plot with the following code ...
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2answers
233 views

Intuitive meaning of complex time domain signal representation (quadrature sampling)

I saw What is the meaning of imaginary values in the time domain?. My question is about I Q samples as recorded from an SDR receiver (e.g. RTL-SDR). My understanding is that we can call these I Q ...
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2answers
753 views

How do I find the convolution of the following signals? [closed]

$h(t)$ is the inputted to convolve the $x(t)$ The signal written in unit step are: $x(t) = (5-t)u(t-3) - (5-t)u(t-5)$ $h(t) = 2u(t-1) - 2u(t-3)$ So to convolve I first change the function to: $h(...
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0answers
69 views

IFFT during ISTFT - and Nyquist

Using a compilable programming language (not Librosa, Matlab, etc), I am attempting to perform ISTFT on filtered (masked) source STFT matrices obtained from NMF. During the original construction of ...
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4answers
892 views

Can every type of linear filter be modelled by a convolution?

I have an input time series going through a filter that creates another time series as output. If I assume in first approximation that my filter is linear, does it necessarily mean that I can model ...
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0answers
54 views

Underwater acoustic channel is giving me a flat BER vs SNR curve

I need to do OFDM and GFDM signal transmission in underwater acoustic channel. I have my underwater acoustic channel as follow. ...
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2answers
444 views

negative value of signals

can we say there is no sound produced when the amplitude is 0? if yes what can we say when the amplitude is negative?
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1answer
42 views

Test for Equivalence of two time series

I wish to test whether two time series are equal. So I believe best way to define equivalence is that given two time series, say $\{x1_t\}$ and $\{x2_t\}$, we show that both the series come from the ...
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1answer
134 views

How to determine the phase of a time-sampled periodic signal?

I know this is a rather common and a rather simple problem, but somehow I can't find a solution that is equally simple to understand (and implement). I have a signal that closely resembles a noisy ...
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2answers
67 views

Is it valid to calculate the magnitude, power, and phase of a real time-domain signal without converting it to the frequency-domain?

I would assume you perform the calculations the same way, but since there would be no imaginary component because the signal is not complex it would be simpler: ...
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2answers
270 views

Why the following discrete type system,variable accumulator, is time invariant?

$y[n]=T{x[n]}=\displaystyle\sum_{k=n-n_{0}}^{n+n_{0}} x[k]$ it is some sort of moving summer which computes $n^{\text{th}}$ output sample by adding all samples lying within length $n_{0}$ around some ...
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2answers
120 views

Can a 1-dimensional signal be in a domain other than the time or frequency domain?

In signal processing I have only heard of signals being in the "Time" domain or in the "Frequency" domain, but are there situations where a signal is not in either of these? If so, what are these ...
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2answers
2k views

Finite and Infinite support in time and frequency domain

It's known that signals with a finite support in time has an infinite support in frequency (talking about Fourier Transforms). A common example that is given for the claim is the triangle function ...
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1answer
80 views

Extracting audio from picture of time-domain signal

I saw this nifty art thing where they dress up the time-domain audio signal in some pretty way. https://www.etsy.com/ArtbloxShop/listing/621561709/sound-wave-art-custom-soundwave-print My question is ...
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1answer
311 views

What is the relationship between the discrete time and continuous time variables?

While going through Proakis's Digital Signal Processing (page 21) ,he stated that if a continuous time signal $~x(t)~$ that has been sampled each $~T~$ seconds to produce a discrete time signal $~x(n)...
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1answer
35 views

Practical insightful time domain functions [closed]

This question might be a little bit different, but i am having hard time to find some sort of a list/book/website/advice, with very practical time domain functions that provides useful insgihts for a ...
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6answers
629 views

Optimal $ n $ -th Order IIR /AR Approximation of a Moving Average Filter

I would like to approximate a moving average filter with an IIR filter of much lower order than the tap-length of the moving average filter. Optimality shall refer to the $L_2$ norm of the impulse ...