Questions on the mathematical aspects of signal processing. Please consider first if your question might be more suitable for http://dsp.stackexchange.com/
Questions tagged [signal-processing]
2068 questions
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building time signal after inverse FFT
I have managed to implement both forward and inverse FFT transforms in C#. And, i tested them by taking signal both ways and got the real part after iFFT equals the original signal.
Now , I have taken the same signal in frequency domain and changed…
M.Dawood
- 3
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Unit of the second derivative of the power spectral density
To characterize a subtle oscillation embedded in a time varying voltage signal measured in microvolts, I took the second derivative of the PSD (which I computed as the fft of the autocorrelation) which nicely amplified the peak so it could be easily…
TThia
- 11
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The set of inputs x(n) to a system is described with a small superscript T - what is that?
I think it means TRANSPOSE, but I can't figure out the need to perform a transpose operation:
Similarly, the set of weights that go with the inputs is written with a small T as well:
There is also some algebraic operation with this T that I don't…
Hassaan
- 199
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Systems properties assistance
I am a little confused about the properties (is it Linear, Causal, Time-Invariant, Stable?) of this T system.
$$T[x(t)]=\sum_{k=t_0}^{t}{x(k)}$$
Some are obvious (it is linear), but can’t come up with the rest of them… any tips on this would be…
Angel Rmz
- 13
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proof that orthogonal signals not interrupting each other
I know that signals that are orthogonal do not disturb each other.
What I am curious is what is the proof behind why orthogonal signals in a single signal (i.e. a single signal can be broken down into signals that have their unique frequency.) do…
user2346
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Is $y[n]=x[n]-x[n-1]$ invertible system?
Well, the title says everything.
I know I can find a z-transform, find $H(z)$ and then find a appropriate invert system and comment on that.
How do I explain it to a person who does not know z-transform?
ponir
- 204
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1 answer
Signal processing very short question?
We have $Y(k)=x(k-1)+ kx(k-5)+x(k)^4$ .I have to find the impulse response for the function
So I know that $G(z) = \frac{Y(z)}{X(z)}$ but how do I relate that to this?
$Y(z)=(z^{-1}) + k(z^{-5})+ z^4$
Xizi
- 13
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Rewrite sinc function
I am working on an exercise in binary transmission systems. The pulses are modeled using a special sinc-function in the time-domain, $f_0$ is the bitrate but just a constant in time domain:
$s(t) = f_0\operatorname{sinc} (\pi f_0(t- \frac 2…
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How can I calculate the frequency when my samples don't span a whole period?
I am taking samples at 30Hz of a signal which is a slowly-varying sinewave.
The period of the sinewave is expected to drift slowly, but will always be somewhere between 0.5s and 2s.
I would like calculate a estimate of the period/frequency of the…
dbruning
- 103
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Find a difference equation for $h_r[n]$
I'm having a signal
\begin{align}
h_r[n] &= r^n \sin\Big( \frac{\pi}{2} n \Big) u[n]
\end{align}
where
\begin{align}
u[n] &= \begin{cases}
1 & \mbox{if } n \geq 0 \\
0 & \mbox{else}
\end{cases}
\end{align}
and I'm supposed to find a difference…
Stefan Falk
- 1,217
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- 24
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Show if signal is time variant or not
I know that I have to show that
\begin{align*}
y[n-n_0] &= f \Big( \{x[n - n_0]\} \Big)
\end{align*}
in order to tell if a signal is time-varying of not.
Having a signal $y[n] = \frac{1}{2}\delta[n] - 2x[n-1]x[n-2]$ is it sufficient to just show…
Stefan Falk
- 1,217
- 1
- 11
- 24
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1 answer
DSP Time domain and frequency domain
I'm new here and wish to say hello to this great community.
I'm starting to learn DSP, I don't have a lot of Maths background but I'm trying to learn.
I am new to DSP too and I am reading this great book: The Scientist and Engineer's Guide to…
lmiguelmh
- 103
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A filter with frequency response $H(f)=\operatorname{sinc}(f).$
In signal processing, a sinc filter is an idealized filter that have the following frequency response
$$H(f) = \mathrm{rect} \left( \frac{f}{2B} \right)$$
that is the rectangular function. In the real world, no filter has a frequency response…
Mark
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Is this signal band-limited?
I'm self-learning signal processing now, and I've run into this question about band-limited signals:
Consider the signal $x(t) = 1$ for $0 \leq t \leq T$ and $0$ otherwise.
I've found that its Fourier transform is:
$$ x_\phi(\Omega) =…
DanielY
- 979
0
votes
1 answer
Verifying by Signal Energy Method?
There's a question in my signal processing textbook that says:
Verify that $\int_{-\infty}^{\infty} sinc^2 (kx)dx = \frac{\pi}{k}$ by signal energy method.
I'm unsure what "signal energy method" means here. I've tried finding the energy ($E_g =…
Rome_Leader
- 381