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ECE302 Homework #2
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Assigned 9/11/11, Due 9/21/11 (by 4:30 in dropbox in MSEE 330)
1. A binary digit, 0 or 1, is transmitted over a noisy channel. The channel either correctly
transmits the digit or it erases the digit, and the receiver knows when an erasure occurs,
but not the value of the digit that was erased. Hence a 0 or a 1 is transmitted, and if a 0
is transmitted then a 0 or an e is received, while if a 1 is transmitted then a 1 or an e is
received (e stands for erasure).
.Assume that the probability that a 0 is received given a 0
is transmitted is 0.8, and the probability that a 1 is received given a 1 is transmitted is 0.9.
Also assume that a 0 is transmitted with probability 0.6.
(a) Find the probability that an erasure occurs
(b) Find the probability that a 1 is transmitted given an erasure occurs.
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 Spring '08
 GELFAND

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