Reference no: EM13495447 , Length: 20

Problem 1: (Digital Communications Systems)

digital Communications uses a few specific modulation formats. Research at least 5 different applications or standards and explain what modulation format is used. For example:

"High-capacity terrestrial microwave systems use double-sideband quadrature modula¬tion, the extension of QPSK, with (up to) 1024 signal points and Nyquist filtering, etc " (you may want to add a reference also)

Problem 2: (Frequency-Shift Keyed Signaling)

Consider the FSK signals from class

and both signal arc active from time 0 to T, that is r(r) is the rectangular on-off function

1) Calculate and plot the spectrum of s₁(t) and s₂(t)

2) Now replace Π_T(t) with P(I), which is a root-Nyquist frequency pulse with a = 0.1. That is. do not chose the time pulse that looks like a sin(x)/x. but the spectral shape from Page 61 of the notes. Sketch both the transmitter side and the receiver side for coherent demodulation.

3) Calculate the spectrum of s₁(t) and s₂(t) for this case. (Remember and make use of the duality theorem).

4) Can you show if these signals are still orthogonal? If not, is there a frequency spacing that makes them orthogonal?