3
votes
Accepted
Quadrature Detector with a single ADC
The sampling offset is a time delay between the I and Q paths. The Fourier Transform of a time delay $T$ is $e^{-j\omega T}$ and thus we see that this will impart a linear phase that is proportional ...
- 37k
3
votes
Sampling and Aliasing
I think the main take away of this whole section is
If you sample a signal in time it becomes periodic in frequency
Let's look at an example: A sinusoidal signal with a frequency of $f = 1Hz$ ...
- 31.4k
1
vote
Accepted
Optimum sampling frequency for decoding analog PDM stream?
uniform-time ADC-based sampling of PDM
no matter how fast you could sample, your ADC needs an analog anti-aliasing filter. That's the key here:
Your AA filtering inherently "sums up" the ...
- 26.1k
1
vote
Quadrature Detector with a single ADC
If you are sampling at 24kHz and each of I and Q are be limited to 4kHz, the effect of one sample offset should be limited. If you want to reduce it further, perhaps you could do a simple linear ...
- 2,186
1
vote
Accepted
FFT to work out optimum number of samples to average
When you take many samples and calculate an FFT, you likely find that noise is flat in the higher portion of the spectrum and for lower frequencies eventually noise will rise proportional to √f or ...
- 312
1
vote
FFT to work out optimum number of samples to average
The optimum number of samples to average over for any series of data which may become non-stationary over longer time intervals is readily determined by using the "Allan Deviation" (ADEV) ...
- 37k
1
vote
Why would the emitted signal from repeating binary data over a wire appear at a frequency lower than the bit frequency?
If you send the same pattern again and again, you have a periodic signal which has a line spectrum and the fundamental frequency is the inverse of the time period.
If you send a random bit pattern at ...
- 31.4k
1
vote
Accepted
How to maintain DFT symmetry for zero padding in frequency domain?
I think the question here is "what to do with the original Nyquist frequency when zero padding in the frequency domain"?
The answer is: "you shouldn't do anything since it should be ...
- 31.4k
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