Radio communication with orthogonal time functions
Henning F. Harmuth · Transactions of the American Institute of Electrical Engineers Part I Communication and Electronics · 1960
Communication systems using orthogonal time functions for the transmission of information over radio links are characterized by the following properties: 1. The same amount of information may be transmitted per unit (pu) bandwidth and pu time with double-sideband modulation as with single-sideband modulation. 2. No phase lock between the carriers produced at the transmitter and at the receiver is necessary for detection by correlation. Hence, communication is less affected by rapid phase changes of the carrier than in systems requiring phase lock. 3. It is possible to operate under conditions of large Doppler shift without changing the frequency of the carrier produced at the receiver, provided the Doppler shift varies sufficiently slowly.