Consider a four-phase PSK signal represented by the equivalent lowpass signal w...

Consider a four-phase PSK signal represented by the equivalent lowpass signal

where In takes on one of the four possible values with equal probability. The sequence of information symbols {In} is statistically independent.

1. Determine and sketch the power density spectrum of u(t) when

2. Repeat Part 1 when

3. Compare the spectra obtained in Parts 1 and 2 in terms of the 3-dB bandwidth and the bandwidth to the first spectral zero.