TABLE OF CONTENTS Multilevel (M-ary) frequency shift keying (FSK) transmits a symbol than represents N= log 2 Mbits of information. An M-ary FSK signal keys the carrier frequency to one of M discrete frequencies during the symbol time T s for the representation of N binary logic signals for the transmission of information. The modulated sinusoidal signal has an amplitude of A V, a carrier frequency of f c Hz, and a 0 reference phase angle, as given by the analytical expression in Equation 3.54.
| (3.54) |  |
On the CD An M-ary FSK coherent digital communication system with AWGN and optimum receiver implemented as a correlator is shown in Figure 3.17 (see Fig3-17.svu on the CD-ROM). To facilitate the simulation in SystemVue, all of the Analysis tokens, except that for the BER token output as the Final Value token, are deleted in the simulation model Fig3-17DT. As described in Chapter 1 the SystemVue Textbook Edition does not permit tokens to be deleted.
The SystemVue simulation presented here is for an M = 4, 4-FSK, but can be easily extended to any 2 N-FSK ( N = log 2 M) digital communication system. This M-ary FSK system is similar to the Gray-coded M-ary ASK system shown in Figure 3.13. The 4-FSK signals are assumed to have equal apriori probabilities of occurrence (
