Wireless digital telephone system base station emulator - initiates synchronisation for assigning time slots to subscriber station within frame pattern of signal using positive edges

摘要

The system uses a modified subscriber station to act as a simulated or emulated base station. This emulated base station essentially differs from the subscriber station only in being able to initiate the synchronization process, whereas the subscriber unit only acts to scan the RF signals sent out by the emulated base station until it finds the frequency and slot assigned to it. The signal received from one station is separated into high band and low band energy frequencies. The high band energy output is substracted from the low band energy output to obtain a resultant signal, which is stripped of its sign determine only the amplitude. The stripped signal is accentuated while substantially filtering out noise, and fed to a voltage controlled crystal oscillator (VCXO) which provides the timing at the other station.