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25th December 2015, 07:50 #1
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Some common Analog terms
1)Why db ranging mostly from 0 to negative? peak at 0 level and as it decreases it goes negative? why no positive?
2)noise floor in 155dBm/Hz what's dBm? why its over frequency?
3)why resisitity express in ohmcm? why cm which is length? not not ohmarea?
4)what 's a epi versus non epi wafer?

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25th December 2015, 09:55 #2
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Re: Some common Analog terms
1) dB can be positive or negative. It's often negative for noise levels and positive for gain or signaltonoise ratio.
2) dBm is the signal power relative to 1 mW. Thus 10dBm is 10dB below 1mW or 0.1mW.
The noise is given per Hz (a 1 Hz bandwidth) so you can calculate the total noise in a given bandwidth because the total noise is proportional to the squareroot of the bandwidth.
3) Resistivity is given per distance for a (theoretical) infinite area of the test material. This means the measured resistance is simply proportional to the distance between the test probes (in this case in cm) times the resistivity.
4) A epi wafer has an epitaxial layer, whereas obviously a nonepi wafer doesn't.Zapper
Curmudgeon Elektroniker
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