ection 5.3.1, you'll get an orthonormal basis {Q1 (t), ...,QN(t)} , and you'd find the basis made up of a cosine and sine. Specifically, you'd find the orthonormal basis is (t),Q2(t)} where = and Now, this is intuitively pleasing, because, looking at Table 5.6, it's obvious that 4- PSK signals are made up of a sum of sines and cosines, and that's what the orthonormal basis tells us: you can write 4-PSK signals as a sum of sines and cosines. Input Output waveforms 4-PSK so(t)=Acos(Wt+O)(t-iT) = s,(t)=Acos(Wt+90)(t-iT) S2(t)=Acos(Wt+180).(t-iT) = S3(t) = Table 5.6 4-PSK written as a sum of sines and cosines Getting It from Here to There: Modulators and Demodulators The Coefficients: Now that you have the orthonormal basis {0,(t),Q2(t)}, , let's move ahead and take a look at the values (501,S02), then (511,S12) and SO on. By doing the simple integration that gives these values (Equation (5.6)), we quickly and easily (sups The Plot: Now we can represent 4-PSK signals on a plot, which will tell us how much Q1(t) and how much Q2(t) must be added together to create the QPSK signal. Take a look at Figure 5.22 and see 4-PSK in a whole new light. 02(t) (0,AV(T/2)) represents S1 (t) represents so(t) 01(t) (-AV(T/2),0) represents S2 (t) (S01, So2)=(Av(T/2),0) (0,-AV(T/2)) represents S3 (t) Figure 5.22 Plot of 4-PSK signals {so(t), (t), s2(t), s3(t)} using orthonormal basis 8-PSK "Must we?" I think as I write this title. "I mean we've already done BPSK and 4-PSK, do we really have to do 8-PSK?" I think about how nice a short book would feel as I write late, late into the night. But, don't worry, after 4-PSK, this one's a breeze, SO we'll just do it and it will be over in no time. Chapter Five Table 5.7 shows you the 8-PSK signals once again, and adds a little to it by showing how each 8-PSK signal can be written as a sum of sines and cosines. You've really got two ways to find the {Q1(t) ,On(t)} (orthonormal basis functions) for 8-PSK. First off, you could jump ahead and use the algorithm of Subsection 5.3.1. Or, if you've go