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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Discrete Signals
Can anyone please tell me
What is the period of $\cos(n) u(n)$?
Here Cosine is multiplied by a unit step sequence .
I am just learning the basics of signals now and I have found that $\cos(t) u(t)$ is aperiodic and no fundamental period in…
sindhu
- 52
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Calculating the SNR of a digital filter by knowledge of the impulse response
Lets say we have a known Impulse response $h[k]$ of a digital filter (e.g. IIR filter) where k is from 0 to $\infty$. Additonally, we have an infinite table of noise data $n[k]$ from which we know that this noise is white. What is the…
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Filtering a signal
So let's say that I have a signal of fundamental frequency 50Hz. I then have a band-pass filter that passes the band between 800 and 1000 Hz of my signal. I don't know the expression of the signals I just know the graphics:
My question now is how…
Granger Obliviate
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Writing cos(π+i) in Cartesian form?
I have a problem writing cos(π+i) in Cartesian form (x + yi). I understand that it is usually written in the form cos(θ) + i sin(θ), but I don't understand how to obtain the sin part (and how to even write this in any other form e.g polar form).
any…
Thijs H
- 79
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Nonlinear single-input single-output model
Assume a single-input single-output model $y = f(x)$ where time series $x = (x_0, .., x_{n})$ is the input, time series $y = (y_0, .., y_n)$ is the output and $f$ a function mapping $x$ to $y$.
If the system $f$ is linear and time-invariant, it is…
foo
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1 answer
Convert 64bit fixed point to 32bit fixed point
If for example two numbers are multiplicated, one is in 8.24 format and second is in 2.30 format, product of those two is number with format 10.54, how to go back to 32bit fixed point format?
Laki
- 155
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Normalized sinc(at)
I came across the definition of the sinc function when it is normalized as sinc(t)= sin(pi.t)/pi.t. So if we scale the argument of the normalized sinc function as sinc(at), will that equal sin(a.pi.t)/a.pi.t? Can anyone pls explain?
Amit Sonik
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Calculate convolution y[n] = (x ∗ h)[n] of signals h[n] and x[n]
I would like to ask, how should I proceed when calculating convolution of LTI systems with the following parameters:
x[n] = 3δ[n+1] + δ[n−1] + 4δ[n−2] − 2δ[n−4]
h[n] = −δ[n + 1] + δ[n] − δ[n − 1]
I do know the result, but I am unfamiliar with the…
raz
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Align shifted similar signals without comparison
I have multiple signals (1-dim. arrays) that are similar as depicted on the image example of 2 similar signals. The signals are circulary shifted. I'm searching for a way to align similar signals without comparing them. In a way, I am searching for…
gntr
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Calculate for a sinusoidal signal with an angular velocity of 314.1593 radians/s and a peak voltage of 340 V
Calculate for a sinusoidal signal with an angular velocity of 314.1593 radians/s and a peak voltage of 340 V
The instantaneous amplitude at t = 15 ms
V(t) = A.sin(ω.t)
V(t) = 340 sin (314.1593 x 15 x 10-3)
V(t) = 340 sin (4.71)
V(t) = 340 * -1 =…
Sameet Sidhu
- 27
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1 answer
Quick way to determine the convolution of two functions
Problem
I'm given the following convolution problem. I distribute the values that correspond to each delta, then add the time shifts. I get the correct solution which is D
But, is it possible to work these problems in a calculator? This problem in…
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2 answers
Why is $1 - 2\cos^2(\frac{\pi n} {4})$ the same as $ -\cos(\frac{\pi n} {2}) $?
Why is $$1 - 2\cos^2(\frac{\pi n} {4})$$ the same as $$ -\cos(\frac{\pi n} {2}) $$
I think the 1 in here, I can just neglect when I look at borders from $[-\infty , \infty]$.
But what's going on with the cosine in here?
madmax
- 439
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Visualize signal drops
I have an input signal (blue) and a mean signal (green) which I compute from from previous signals). They looks like this:
(I also have the standard deviation signal and can do others if needed.)
From these signals I whish to clearly visualize two…
Jonas Byström
- 165
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LTI system with sinc input and unit impulse output?
I have a few "conceptual" questions given to me in preparation for a signals and systems exam, and I can't seem to grasp this one.
Does there exist a linear time-invariant (LTI) system S such that:
$$x[n] = \frac{sin(\frac{\pi}{8}n)}{\pi n} \quad…
JackD
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Why is the following system is not time invariant?
The system is as follows: $y[n] = x[2n]$
Shouldnt the system be time invariant because
$y[n-n_0] = x[2n-2n_0]$
and
$T(x[n-n_0]) = x[2n-2n_0]$
These are both equal, therefore why is the system not time invariant?
Jason
- 3,563