Questions tagged [interference]
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58 questions
0 votes
1 answer
56 views
Deriving MMSE equalizer, how is $\mathbb{E}[d_kd_l]=0$ when $k\neq l$ for input symbols?
I have read MMSE equalizer for ISI affected channels from three books: Digital Communication by Proakis Principles of Mobile communication by Stuber Wireless Communications by Andrea Goldsmith In ...
- 195
0 votes
0 answers
72 views
Zero forcing equalizer matrix
I am looking for an explanation of the matrix used in the Zero-Forcing equalizer, what its rows and columns represent, and why we focus on the middle row? In the zero forcing we use $2N+1$ samples ...
- 109
0 votes
1 answer
194 views
Inter symbol interference
I understand the Nyquist criterion in the frequency domain, which specifies that for zero inter-symbol interference (ISI), the signal's bandwidth should be limited to $\frac{R_{b}}{2}$, where ${R_{b}=\...
- 109
1 vote
1 answer
102 views
How to check if the number of samples used to build a covariance matrix is enough?
How can I determine if the number of samples used to construct a covariance matrix is enough to ensure accurate and stable estimation of the matrix? My application is RF. I need covariance matrix to ...
- 89
0 votes
1 answer
136 views
How to relate a section of a PSD plot back to the original complex numbers IQ or remove part of a signal from a spectrum with python-signal excision?
I have data coming off an software defined radio, I want to remove a certain signal(interference) from a spectrum new to DSP. I am using python. the signal comes in as an array of complex numbers (...
- 19
1 vote
0 answers
69 views
How can it be possible that I hear people voice from my computer speaker?
I searched on web and apparently can be due to truck drivers communicating at CB band which is around 20MHz. And apparently this communication may interference with the frequencies used by computer's ...
- 125
0 votes
1 answer
106 views
What is the most used signal for basic pulse?
My professor said that: in order to avoid interferences/harmonics caused by the nature of the square wave g(t) (sinc will have these secondary lobes), it's better to change the basic pulse g(t) to ...
- 125
1 vote
2 answers
114 views
Since harmonics only generate at multiples of the center freq, is it for this reason that the left part of a FT (like sinc) has no physical meaning?
If we have a rectangular pulse function, we know that after a Fourier transform we obtain a sinc: We know that the left part (negative frequencies) has no physical meaning and it's just specular. It'...
- 125
0 votes
0 answers
50 views
Tracking period of quasi-periodic transient type signal in strong non-stationary interference
Consider a desired (pink) signal as well as its observation in heavy, non-stationary interference (green, this is the desired signal plus interference). As seen in the plot, the interference can also ...
- 513
0 votes
0 answers
76 views
Hilbert Transform matches signal rather than envelope
I have an interferogram of a white LED. I am trying to extract the envelope of the signal. Shown is the interferogram, and the absolute value of the Hilbert Transform of the interferogram. I used <...
1 vote
1 answer
246 views
Fractionally spaced equalizer - LMS algorithm
I am doing a project in MATLAB about the fractionally spaced equalizer. The method that i have chosen to update the tap weight coefficients is the LMS algorithm. Here is the block scheme that i have ...
- 81
0 votes
1 answer
67 views
How can I simulate a random delay offset between two data streams?
Suppose I'm transmitting two streams at the same time in blocks each of length $N$ samples each sample of duration $T_s$ seconds. Block $t$ of stream $i$ is $\mathbf{x}_i[t]=\left[x_{i,0}[t],\,\,\,x_{...
- 141
3 votes
0 answers
145 views
Emergence - what constitutes a minimally coherent source that "just begins" to produce stationary interference patterns?
A superposition of two signals with different frequencies will never produce visible (i.e. stationary) interference patterns. Such waveforms will produce spatiotemporal beat patterns, but they rapidly ...
- 131
0 votes
2 answers
75 views
Reconstructing a wave which interferes together with a second known one
Is it possible to calculate one of two interfering waves, if the interference (the sum) $v$ and the other wave (summand) $v_1$ is known? The waves have same frequency but may differ in phase and ...
- 13
3 votes
0 answers
140 views
How does matched filter output provide sufficient statistic when the channel has ISI + AWGN?
In Forney’s MLSE paper (link: https://ieeexplore.ieee.org/document/1054829), Forney mentioned that the matched filter output is still sufficient statistics even with ISI (second column on page 365). I ...
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