B Can a filter based on the photoelectric effect reduce the noise floor?

[danielhaish]

TL;DR Summary

According to the photoelectric effect low frequency em can't be observed by electrons in the atom , and the noise floor is effected by the frequency dense. Therefore if you signal is in low frequency the noise of higher frequencies won't effect it.

Assume you transmitted in low frequency the floor noise would still be effected by other frequencies due interference. But is it possible to reduce the noise created by higher frequency sources by blocking them in a way that won't block the photons transmitted by your source . So even tho by regular antenna you would normally observe the noise as being in low frequency even tho it only a result of higher frequency being create noise in lower frequency due interference

 

[marcusl]

You seem to be mixing up concepts that are unrelated. The photoelectric effect is a quantum phenomenon while antennas, signals and filters are classical.

 

[danielhaish]

You seem to be mixing up concepts that are unrelated. The photoelectric effect is a quantum phenomenon while antennas, signals and filters are classical.

True but if it was somehow possible build a filter that based on such an effect instead of escalation in a conductor you could isolate the effect of other frequency on you signal

 

[marcusl]

Do you have a specific question?

 

[DaveE]

True but if it was somehow possible build a filter that based on such an effect instead of escalation in a conductor you could isolate the effect of other frequency on you signal

This is done ALL THE TIME in electronic systems. Really, ALL THE TIME. Noise has a frequency spectrum. We use filters to only measure the frequencies we are interested in. This is why when you tune in a radio station you don't also get the nearby (in frequency space) station as noise. A huge part of virtually every electronic circuit design task is keeping the stuff you want and getting rid of the stuff you don't want.

Maybe spend a bit of time learning about radios, spectrum analyzers, Fourier Transforms, lock-in amplifiers, etc. Start with Fourier Transforms if you're ready for that math.

 

[danielhaish]

This is done ALL THE TIME in electronic systems. Really, ALL THE TIME. Noise has a frequency spectrum. We use filters to only measure the frequencies we are interested in. This is why when you tune in a radio station you don't also get the nearby (in frequency space) station as noise. A huge part of virtually every electronic circuit design task is keeping the stuff you want and getting rid of the stuff you don't want.

Maybe spend a bit of time learning about radios, spectrum analyzers, Fourier Transforms, spectrum analyzers, lock-in amplifiers, etc. Start with Fourier Transforms if you're ready for that math.

The point is that there is a noise floor effected by other frequencies for isntance strong transmission in low frequency can raise the entire noise floor due spectral leakage

 

[DaveE]

The point is that there is a noise floor effected by other frequencies for isntance strong transmission in low frequency can raise the entire noise floor due spectral leakage

Yes, in a non-linear systems mixing happens. Still, the noise at the locations of interest has a defined spectral content.

This is why non-linear subsystems, like mixers, samplers, power amps, etc. are nearly always accompanied by filters

The "noise floor" usually isn't a strong transmission. IRL, strong transmissions usually have a high spectral content and will create identifiable mixing products. The noise floor is usually from more thermodynamic processes with a broad emission spectrum and limited power at any single frequency; like black body radiation, white noise, 1/f noise, shot noise, etc. You'll see this when you reduce the bandwidth of your spectrum analyzer (or not). This is why synchronous detection (like with a lock-in amplifier) is so effective. There is a bit of semantics here. The noise in your system is what it is, you can call it a noise floor if you want. It likely comes from several processes.

 

[danielhaish]

Yes, in a non-linear systems mixing happens. Still, the noise at the locations of interest has a defined spectral content.

This is why non-linear subsystems, like mixers, samplers, power amps, etc. are nearly always accompanied by filters

The "noise floor" usually isn't a strong transmission. IRL, strong transmissions usually have a high spectral content and will create identifiable mixing products. The noise floor is usually from more thermodynamic processes with a broad emission spectrum and limited power at any single frequency; like black body radiation, white noise, 1/f noise, shot noise, etc. You'll see this when you reduce the bandwidth of your spectrum analyzer (or not). This is why synchronous detection (like with a lock-in amplifier) is so effective. There is a bit of semantics here. The noise in your system is what it is, you can call it a noise floor if you want. It likely comes from several processes.

What I mean is that also in linear systems the frequency floor is effected by low frequency component due phenomenas such Low-Frequency Modulation and other phenomena caused by interference .regular filters follow superposition which means they wont be able to remove the noise crested by interference pattern with other frequencies. But I was thinking to filter those frequencies from mixed signal by using effect that requires photons to be in spesfic frequency such as the photoelectric effect

 

[berkeman]

What I mean is that also in linear systems the frequency floor is effected by low frequency component due phenomenas such Low-Frequency Modulation and other phenomena caused by interference .regular filters follow superposition which means they wont be able to remove the noise crested by interference pattern with other frequencies. But I was thinking to filter those frequencies from mixed signal by using effect that requires photons to be in spesfic frequency such as the photoelectric effect

Okay, due to the language barrier here in your posts, you really need to start posting the mathematics behind what you are saying. Your words are just a jumble right now, so hopefully you can use math instead to explain your question. I will send you a DM with tips on how to post your math using LaTeX.