Abstract :
It is proposed that the previously described QNX matrix [1] be used to provide the information content for quadruplex FM transmission, QFMX. In this proposal, a true, omnidirectional signal ´T appears in the baseband of the composite FM modulating signal, while a directionally encoded stereodifference signal T modulates the normal-phase 38-kHz subcarrier and a conjugately>encoded difference signal T modulates the quadrature-phase 3w-kHz subcarrier. The fourth signal TQ is provided via SSB (single sideband) modulation of a synchronized 57-kHz subcarrier, using the upper sideband. The bandwidth of TQ may be selected at the broadcaster´s option to be 3 kHz, if SCA (subsidiary communication authorization) is to be used, or 15 kHz if SCA is not to be used. If used, the SCA signal may occupy the band from 64 kHz to 91 kHz, or some fraction thereof. Suitable pilot signals are provided, at 19 kHz, 57 kHz, and 95 kHz.
