The bit stream 01001 is differentially encoded using 'Delay and Ex OR' scheme for DPSK transmission. Assuming the reference bit as a '1' and assigning phases of '0' and '$$\,\pi $$' for 1's and 0's respectively, in the encoded sequence, the transmitted phase sequence becomes

Coherent demodulation of FSK signal can be effected using

For a random variable 'X' following the probability density function, p (x), shown in figure, the mean and the variance are, respectively.

The maximum power efficiency of an AM modulator is