EE 164 Problem Set 10

EE 164 Problem Set 10 - EE 164 Problem 1: Problem Set 10...

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EE 164 Problem Set 10 Spring 2005 Problem 1: Design an analog modulator like that shown in the below figure by using a silicon transistor. For this transistor, 60 β = .Set the DC bias at 50 mA . 50 , in R = 3, a R K =Ω 6 b R K and the bias supply voltage is 10 V . When the light source is on, its voltage drop is 1.8V. in V in R b R a R c R C dc V c e b B I c I E I LED a) Compute the value of the emitter resistance e R . b) Compute the collector-emitter voltage at the Q point. c) Figure out the maximum modulation factor this circuit can provide. Problem 2: The LED whose output characteristic is shown in the below figure is used in a two-channel frequency-division-multiplexed system. The LED total harmonic distortion is measured as 25 dB when a sinusoidal current with a 50 mA peak is applied. The bias current is set at 50 mA. The AM modulation of each subcarrier is 50%. The intensity modulation is 100%. The subcarriers are at 1 MHz and 2 MHz and have equal peak currents. The information is a1000 Hz tone for both
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This note was uploaded on 03/23/2011 for the course EEE 174 taught by Professor Kasab during the Spring '11 term at ASU.

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