Modulation techniques for land mobile radio

PM systems with 12.5 kHz and 25 kHz channel spacing have been compared with 12.5kHz AM and 5kHz SSB systems, and the effect of applying companding techniques to SSB as well as to PM has been investigated. The systems have been compared with respect to audio signal quality, speech intelligibility, spectrum utilization and applicational flexibility. The traditional - uncontrollable - field trials have been replaced by laboratory tests using advanced propagation simulation techniques, and the analysis has included pulse noise susceptibility and performance with multipath fading. The overall conclusion is that 12.5 kHz PM provides the best balance between transmission quality, spectral economy and applicational flexibility.