Use of SPADE Channel Unit Equipment in a SPAPE System with Preassigned Channels.

Equipment to be used in a ″single-channel-percarrier PCM multiple access preassigned system″ (SPAPE) is described. SPADE channel unit modules are used in such an equipment which is implemented to be linked to conventional networks with voice frequency interfaces or to data networks with digital interfaces. Data are transmitted at 2 MBs rate, corresponding to a 30 channels TN1 group as specified by CEPT. In this case digital channels are flown out from the TN1 equipment and signaling bits are inserted into data. IF access is provided in the 7MHz band both for transmission and for reception. On the transmit side, four-phase PSk modulation is used in a conventional modulator. The demodulator receives bursts of signal which are activated by presence of voice at transmit terminal. Specially suited circuitry is necessary for carrier and rhythm recovering. Demodulator scheme is analyzed.