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 ΠT(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?