Radiotelephone system with receiver sensitivity switching - using automatic lower sensitivity selection for receiving free signal and higher sensitivity for speech signals

摘要

The system has a fixed transceiver communicating with a number of mobile transceiver units, to allow the latter to communicate with one another or with a normal telephone subscriber. The fixed transceiver provides a free signal for each respective transceiver unit unless it is supplied with speed signals for the latter. The free signal is transmitted at a sufficient signal strength for each mobile unit to operate at a lower sensitivity than during reception of the speech signals, with the switching between the two sensitivity levels effected automatically. The signalling power and the reception sensitivity during transmission of the free signals are 6 decibels lower than those used during transmission of the speech signals.