Questions tagged [time-domain]

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One-sided spectrum consisting of some delta-impulses

If we have a one-sided spectrum consisting of some delta-impulses, what can we conclude about the time domain signal? Is this signal causal, anti-causal, or acausal? Also, I know that since the ...
707 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 ...
23 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. ...
33 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 ...
44 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 ...
46 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: ...
71 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 ...
64 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 ...
99 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?
59 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 ...
82 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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33 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 ...
151 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 ...
105 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 ...
341 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 ...
772 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 ...
57 views

Complex FFT reversing

I've succeeded to compute complex FFT of a data array of interleaved values using the arm_cfft_f32() API of the CMSIS DSP library for Cortex-M4, and got in the same array the FFT results as frequency ...
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279 views

Convolution and Modulation Theorem with Octave Example

As far as I know, convolution theorem stated that $$x[n] * y[n] = X(e^{j \omega}) Y(e^{j \omega})$$ $$X(e^{j \omega}) * Y(e^{j \omega}) = x[n] y[n]$$ I tried a simple experiment using GNU Octave ...
331 views

Confused on the difference between the frequency spectrum of an entire song, and the frequency spectrum of a point in time

I am very much a beginner in this field - but find it really interesting. However I am a little confused on a certain area of knowledge. If I have understood correctly: At any point in an audiosignal,...
201 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 ...
27 views

Does waveform-based ASR with lowpass filtering preprocessing still require the assumption of FFT?

I read some recent papers about time-domain speech recognition, and wondering if it steers away from the stationary assumption of FFT. However, some preprocessing operations like pre-emphasis and low-...
962 views

Is it possible to apply a frequency filter a time domain signal?

Is it possible to frequency filter a time domain signal, without converting the signal to a frequency domain.. My question comes in regards how MFCC according to wiki and other pages describe the ...
47 views

Index of stationarity of a time domain signal

During my internship, I've come across a software that calculates a percentage called "Index of stationarity". This index shows how much stationary is the signal. Does anyone have any idea on how to ...
1k 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'...