4.4 A binary digital communication system employs the signals So(t) = 0 S₁(t) = A 0≤t≤T for transmitting the information. This is called on-off signaling. The demodulator cross- correlates the received signal r(t) with s(t) and samples the output of the correlator at t+T. a. Determine the optimum detector for an AWGN channel and the optimum threshold, assuming that the signals are equally probable. b. Determine the probability of error as a function of the SNR. How does on-off signaling compare with antipodal signaling?