7
votes
How do EMI noise currents actually appear on a wire?
Induced means that a voltage appears across the wire, so both ends are not at the same potential. When we draw a line in a schematic we typically assume that the potential is identical everywhere ...
6
votes
Accepted
Lowest processable signal level after FFT with given noise level
First observation: the FFT is simply the wrong tool here. You're only interested in a single frequency at 1/192 of your sampling rate. To build an FFT-based estimator for that where as much energy of ...
- 100k
4
votes
How do EMI noise currents actually appear on a wire?
For an interfering current (\$I_n\$) to be produced, the wire must have inductance (my red addition) and a closed circuit for that current to flow: -
It is the inductance (and the resulting voltage ...
- 473k
3
votes
Lowest processable signal level after FFT with given noise level
If a phase reference is available this would be a perfect application for phase-sensitive or lock-in detection.
- 1,526
2
votes
Polarize and monitor a large resistor like device
I have LED lighting in my lab that I have to switch off when performing noise measurements, since they radiate horrendous RF. I also have an LCD screen which produces similar crap even when switched ...
- 47.1k
2
votes
Accepted
Is the use of optoisolators to isolate and clean a signal before an OR gate input good practice? If not what is better?
If you’re creating an alarm system for an industrial customer, you should look into a concept called Fully Supervised Loop. FSL systems use switch and end-of-line terminators to detect whether a loop ...
- 58.2k
1
vote
Is wider component spacing on a PCB less noisy?
Fields attenuate with distance. On the other hand, the larger the loop area, the bigger the antenna.
So, if you have a noisemaker like a DC-DC converter, and a sensitive analog circuit, you'd want to:
...
- 81.6k
1
vote
Is wider component spacing on a PCB less noisy?
As a general case is it true that an analog board with components
spaced out is less noisy than one with a more compact layout?
Generally not true at all.
Consider a tightly spaced design; the ...
- 473k
1
vote
Accepted
Finding Gain of the Analog circuit
The Cross-Coupled Pair
The cross-coupled pair you see in this circuit is widely used for many purposes. It presents a negative resistance which is useful in oscillators and amplifiers to boost the ...
- 1,101
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