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Questions tagged [psd]

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2 votes
0 answers
36 views

Noise floor of an unmatched resistive network thru PSD calculations

I am modeling the PSD of various loads to calculate noise floors. I have various load terminations from 25 ohms to 250 ohms. Per Johnson-Nyquist, the noise floor on a resistor when load and source are ...
Arsch's user avatar
  • 21
0 votes
0 answers
42 views

Image downsampling by a fraction

I need to downsample an image (bitmap image of a Spectrogram) by a fraction, N/D, (rational: ex 4/5). I understand that this can be done with resampling by 4 followed by decimation by 5. If this is ...
user37997's user avatar
  • 121
0 votes
0 answers
95 views

What is the unit of power spectral density?

I have an oscilloscope data, I did plot in time domain, so that unit is in volts (Y axis). After that I took FFT. So now what will be the unit in Y axis? If I will do 10 log 10 (y axis) can it is ...
ARATHI P's user avatar
4 votes
2 answers
504 views

What is the basic circuit to wire up a position-sensitive detector, or PSD?

I'm a software dev dabbling in electronics and I am looking into wiring up a position-sensitive detector, the Hamamatsu S3932, on a breadboard. My knowledge is quite rudimentary and my first goal is ...
cmc's user avatar
  • 267
0 votes
1 answer
2k views

How to convert amplitude (V) to dB (V^2/Hz or V/sqrt(Hz) or V?)

I took the FFT of a signal and am currently plotting amplitude (V) vs. frequency (Hz). I'd like to change the Y-Axis units to dB. How would I go about doing this? What would be the units? It is from ...
Michael Joseph's user avatar
0 votes
1 answer
101 views

What is omega supression for a lock-in amplifier?

I'm using a lock-in amplifier for PSD measurements. The lock-in amplifier has an option for omega supression (in dB.) I'm unable to find resources on the lock-in amplifier's manual or online about ...
Lullapalanza's user avatar
1 vote
1 answer
249 views

Noise Floor of ADC using PWELCH

While using MATLAB's Pwelch function, I am not able to match the noise floor of the "Modelled" ADC to (Delta)^2/6 {1 sided Spectrum}. ...
Preetham Reddy's user avatar
1 vote
2 answers
493 views

PSD vs FFT of voltage magnitude squared and oscilloscopes

Imagine we have a time-domain signal which is a voltage signal. Now if we sample this at the correct rate, and taking the Fourier transform gives us the magnitudes of various frequency components ...
user1999's user avatar
  • 1,505