Solutions_Homework3

# Solutions_Homework3 - GEORGIA TECH LORRAINE GEORGIA...

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GEORGIA TECH LORRAINE GEORGIA INSTITUTE OF TECHNOLOGY School of Electrical and Computer Engineering ECE 6543 Fiber Optic Network Spring Semester 2009 Problem 1 See below Problem 2 1. The photocurrent is i s ( t ) = RP 0 (1 + mcosωt ). The mean-square value is given by < i 2 s ( t ) > = ( RP 0 ) 2 < (1 + mcosωt ) 2 > t . The evaluation of the bracket expression gives us < i 2 s ( t ) > = ( RP 0 ) 2 (1 + m 2 / 2) 2. The value of the noise sources are: Thermal noise < i 2 thermal > = 4 kTB R L = 1 . 6510 - 14 A 2 Shot noise < i 2 shot > = 2 qRP 0 B = 1 . 2810 - 16 A 2 3. The signal to noise ratio is 480. Problem 3 1. For a voltage v , the expression of P 0 ( v ) and P 1 ( v ) are: P 0 ( v ) = Z v th p ( y | 0) dy (1) 1

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P 1 ( v ) = Z v th -∞ p ( y | 1) dy (2) 2. With the assumptions made in the text: P 0 ( v ) = 1 2 πσ 2 Z V/ 2 exp ( - V 2 / 2 σ 2 ) dv = 1 2 " 1 - erf V 2 2 σ !# (3) P 1 ( v ) = 1 2 πσ 2 Z V/ 2 -∞ exp ( - ( v - V ) 2 / 2 σ 2 ) dv = 1 2 " 1 - erf V 2 2 σ
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## This note was uploaded on 09/01/2010 for the course ECE 6543 taught by Professor Boussert during the Spring '09 term at Georgia Institute of Technology.

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Solutions_Homework3 - GEORGIA TECH LORRAINE GEORGIA...

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