A common-wave duplex pulse-communication system

The paper details the principles of a duplex pulse-communication system using only one carrier frequency and suited for air-to-air and air-to-ground radiotelephony. The duplex facility is achieved by suppression of the receivers at each end of a communication link. Pulsephase modulation is employed and the pulse-recurrence frequencies of the transmissions in the two directions are unsynchronized. By using a memory pulse-phase discriminator, the introduction of noise of any considerable level is avoided.