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Johnson noise & Shot noise

  1. Dec 13, 2006 #1
    I was wondering if someone could give me some ways to combat Johnson noise and shot noise.

    Thanks
     
  2. jcsd
  3. Dec 13, 2006 #2

    berkeman

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    Staff: Mentor

    Sure. What is the context? If it's noise in a sensor, what is the sensor technology? How much amplification do you need? What is the bandwidth and character of the signal that you are amplifying? What kind of back-end processing are you doing of the signal?
     
  4. Dec 13, 2006 #3
    There isn't really a context. I'm in an instrumentation class, and one of the questions is "Describe the origins of Johnson noise and Shot noise and appropriate countermeasures you can take to deal with them."

    I know what they are, but I've been trying for the life of me to find out what the countermeasures are. I don't have them in my class notes and they're not in the textbook.
     
  5. Dec 13, 2006 #4

    berkeman

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    Staff: Mentor

    Well, tell me a little about the effects of temperature and bandwidth on each.
     
  6. Dec 14, 2006 #5

    vanesch

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    A simple way is to write down the equations giving their spectral density and/or their integrated RMS constribution, and to see what factors lower it. Hint: lowering the temperature might help for Johnson noise. But also other things play a role. Now look at the other quantities in the formulas...
     
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