Multi-h-phase coding

Abstract

<p>The main objective of this thesis is to investigate the spectral properties of Multi-h phase coding and to consider the trade-offs between error performance and bandwidth occupancy for this modulation method.</p> <p>There are multi-h phase codes which allow for a wide range of trade-offs. For example, there is a bandwidth efficient code which occupies 23% less bandwidth than Fast Frequency Shift Keying (Fast FSK) but required 2.4 dB more power to give the same noise immunity. There is also a code that needs 40% more bandwidth than Fast FSK but yields the same transmission quality with a 3.7 dB savings is power.</p> <p>The power spectrum of a multi-h code is line-free and the tail of the spectrum rolls off as 1/f⁴ as in Fast FSK.</p> <p>Three different methods for spectral analysis are presented and compared. We have found that approaches based upon the Wiener-Khinchin Theorem are to be preferred.</p> <p>Pelchat's analysis of binary FSK with continuous phase is extended to the general multi-index case.</p> <p>A multi-h code can be modelled as Markov chain and the auto-correlation function can be calculated using the theory for such processes. We have devised a simple procedure for identifying the states of the Markov chain.</p>