receiver (assuming each transmitted signal is equally likely). Solution: Turning back the pages to Example 5.4, you'll see we already decided that the receiver front end is as shown on the left of Figure E5.7. On the right side of Figure E5.7 is the decision device. As we just said in the text, it consists of 1. The processor, which in this case inputs V=V, and outputs M=2 branches. The top branch puts out the value of V1-S01/2 and the bottom branch outputs the value V1-S11/2. 2. The adders (or lack of them!): with all symbols being equally likely, (so)=p(s). Hence, there is no need for the adders here since all they would do is add the same number to each branch. The "choose min" device: The choose min device outputs the BPSK symbol closest to the received signal. Chapter Five ri-501/2 r (t) Choose r1 S11 2 receiver front end decision device Figure E5.7 The receiver for deleting BPSK symbols The Matched Filter Receiver-Version 1 Engineers, being creative types, came up with a second way to build the demodulator, shown in Figure 5.29. Let's look at this figure, and compare it to our original figure, Figure 5.28. First, look to the right of the dotted line (at the decision device): on the right of the dotted line, you can see that the two figures are identical, meaning that the two decision devices are identical. Next, glance to the left of the dotted line (the receiver front end) : the two look quite different. But I'm going to show that in fact these two receiver front ends do exactly the same thing, by demonstrating that the input and output of the receiver front end in the new figure (Figure 5.29) are identical to the input and output of the receiver front end in the original receiver figure (Figure 5.28). This means a filter with impulse response h(t)=01(T-t) -20 2 In p(s1) Ir-s1/ (T-t) Choose table (bits) ON(T-t) -20 21 p(sM) receiver front end decision device Figure 5.29 The matched filter receiver-Version 1 Getting It from Here to There: Modulators and Demodulators Both the receiver front ends receive as i