Abstract :
Spectrum is a multidimensional quantity. Considering this, AM, SSB, FM and digital modulation are compared for best spectrum utilization. The evils of high transmitter power are enumerated and some system configurations using low power are discussed. In particular, Prearranged Communication Path (PCP) systems using chains of low power repeaters are described. Looking into the future, it is predicted that PCP Systems using Delta Modulation will be widely used, providing improved service with privacy and much better spectrum utilization.
