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    • PS Helper
    • Thread Starter

    PS Helper
    Not sure if I've went about this the right way?

    The question asks:

    An alphabet consists of the letters A, B, C, D. For transmission each letter is coded into a sequence of two binary (on-off) pulses. The A is represented by 00, the B by 01, the C by 10 and the D by 11. Each individual pulse interval is 5 msec.

    (i) Calculate the average rate of transmission of information if the different letters are equally likely to occur.

    (ii) The probability of occurrence of each letter is respectively P(A) = 1/5, P(B) = ¼, P(C) = ¼, P(D) = 3/10. Find the average rate of transmission of information in bits per second.

    My answer is:
    (i) \frac{1}{T} * \log_2 (\frac{1}{P}) = \frac{1}{0.005} * \log_2 (2) = 200 bits/sec

    (ii)\frac{1}{T} * \displaystyle\sum_{i=1}^M P_i log_2  (P_i) =  \frac{1}{0.01} * \left[\frac{1}{5}\log_2 (5) + \frac{1}{4}\log_2 (4) +  \frac{1}{4}\log_2 (4) + \frac{3}{10}\log_2 (\frac{10}{3})\right] = 198.5  bits/sec

    Are those the right answers and is my method correct?
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