lec28_handout

lec28_handout - From last time Average signal power 1 RMS...

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ME365 Noise and Noise Rejection 1 From last time… Average signal power RMS voltage Signal to noise (power) ratio – noisiness of signal Noise figure – noisiness of system Power spectral density ݔ ݐ 1 ܶ නݔ ݐ݀ ݐ ݔ ݐ ௥௠௦ ݔ ݐ SNR ൌ ݏ ሺݐሻ ݊ ሺݐሻ NF ൌ SNR ௜௡௣௨௧ SNR ௢௨௧௣௨௧ ME365 Noise and Noise Rejection 2 Sources of Noise Internal Thermal (Johnson) Noise Temperature-induced random motion of the electrons in resistors and semiconductors causes a corresponding random voltage. – Johnson Noise is a type of white noise with uniform power spectral density: where – Thermal noise amplitude roughly obeys a Gaussian distribution. – Can only be reduced by reducing temperature and measurement
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3 Shot Noise Quantization of electrons causes fluctuation of current flowing through transistor junctions. – Shot noise is white noise with a uniform power spectral density: for current measurement: for voltage measurement: where Q: What is the RMS voltage due to Johnson and Shot noise? Sources of Noise
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This note was uploaded on 12/26/2011 for the course ME 365 taught by Professor Merkle during the Fall '07 term at Purdue.

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lec28_handout - From last time Average signal power 1 RMS...

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