New answers tagged digital-communications
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What does the frequency domain of bipolar Alternate Mark Inversion (AMI) look like?
Calculating the power spectrum of the AMI code is actually a quite complicated matter, but the fact that the power spectrum has a zero at DC seems intuitively clear, as already mentioned in RBJ's ...
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What does the frequency domain of bipolar Alternate Mark Inversion (AMI) look like?
Okay, so "Google is my friend" and I found a YouTube.
Bits that are zero contribute nothing to the DC component.
If the number of ones in a message is even, it's as positive as often as it ...
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Typical values of Amplitude and Phase Imbalance (IQ Imbalance) in 802.11ax (Wifi 6)
There's no such thing as a an expected imbalance in a communications standard. That's a property of the radio device, not of the standard!
In my humble experience, receiver imperfections vary a large ...
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Impulse response and amplitude-frequency characteristic of a communication channel
There's something off with the units.
$LC$ has unit $\left[s^2\right]$, so the square root has unit $\left[s^2 + F\sqrt{s}\right]$ which doesn't make sense.
In any case, once that's fixed, use ...
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Related to Additive white Gaussian noise (AWGN)
The zero-mean assumption rests on empirical validation. You can do it yourself: turn on an oscilloscope and set it to the minimum amplitude. You'll see noise with roughly zero mean. Intuitively, this ...
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Power Spectral Density and Total Power Calculation for Signal
By the Wiener–Khinchin theorem, the power spectral density (of a power signal) is equal to the Fourier transform of the autocorrelation function. Therefore, one way to proceed is to analytically ...
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Help me understand the concept of IQ signals
It might be best to compare an IQ signal with complex numbers, or circle on an XY plane, or phasors.
As the IQ signal is a sum of sine wave with some amplitude and cosine wave with some amplitude, the ...
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Help me understand the concept of IQ signals
The important takeaway is: using a radio, you can transmit two signals "at the same time" (technically: over the same bandwidth). One of the signals is known as I (in-phase), the other as Q (...
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Help me understand the concept of IQ signals
In SDRs, multiplying a real-valued bandpass signal by a cosine wave, and simultaneously multiplying that real-valued bandpass signal by a sine wave, generates a complex-valued signal that has been ...
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What is the relationship between Symbol Duration and Sampling Frequency in a 256 MPSK radio link
There is a difference between the information bits that you are sending and the bits that represent the samples that you obtain at the receiver. Each sample should be represented by high enough number ...
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How is the normalized power required for unipolar NRZ twice that of polar NRZ?
If the levels of the polar signal were $\pm V$ you would be right, but then it wouldn't be a fair comparison with the unipolar signal with levels $+V$ and zero. A fair comparison would be to have the ...
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80-tap Decimation Filter: divide into stages? / Cost of having a number of taps
This is a bit late to the game and it depends on the decimation factor, but recently I've been working on a multichannel SDR receiver and in doing so stumbled on this article about half-band filters. ...
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