d Systems is treated like the correlator output of the coherent BPSK demodulator. With interleaving and deinterleaving we have a discrete memoryless binary input quantized output coding channel suitable for the usual binary codes with cor- responding decoders. Although the above conversion of an FH/MFSK channel into a discrete memoryless binary input channel was based on a Rayleigh fading channel with receiver and jammer Gaussian noise statistics, it can certainly be used in other cases as well. It is a straightforward conversion and should be robust in the sense of being good for all cases of interest. Generally, for Gaussian noise and optical signals with M-ary pulse position modulation good binary convolutional codes with these converted binary input channels perform as well or better than M-ary input channels for roughly the same complexity (see Lee [33]). For very high speeds and large M, Reed-Solomon codes look attractive for the hard decision M-ary channels. Reed-Solomon codes at data rates over 100 Mbpsa exist for M = 28 = 256 [21]. 2.8 REFERENCES [1] R. C. Dixon, Spread Spectrum Systems, New York: John Wiley, 1976. [2] A. J. Viterbi and I. M. Jacobs, "Advances in Coding and Modulation for Noncoherent Channels Affected by Fading, Partial Band, and Multiple Access Interference," in Advances in Communication Systems, Vol. 4. New York: Academic Press, 1975, pp. 279-308. [3] A.J.Viterbi, Principles of Coherent Communication, New York: McGraw-Hill, 1966. [4] J.I. Marcum, "Table of Q-Functions," Rand Corporation Report RM-339, Jan. 1, 1950. S. W. Houston, "Modulation Techniques for Communication, Part I: Tone and Noise Jamming Performance of Spread Spectrum M-ary FSK and 2, 4-ary DPSK Waveforms," Proceedings of the IEEE National Aerospace and Electronics Conference (NAECON '75), Dayton, Ohio, June 10-12, 1975, pp. 51-58. [6] A. J. Viterbi, "Spread spectrum communications-Myths and realities," IEEE Commun. Mag., vol. 17, pp. 11-18, May 1979. [7] B. D. Trumpis, "On the optimum detection of fast frequency hopped M