| 摘要 |
<p>In equipment for wireless transmission of telephone calls between a stationary unit connected to a telephone line and a portable wireless telephone handset at a short distance from the stationary unit, all the pairs of units have access to a plurality of common duplex radio speech channels for transmitting the calls, and a common radio signalling channel for transmitting signals concerned with establishment and disconnection of the speech channels. The radio speech channels are assigned after adaptive channel scanning in that they are listened-into before a call and a channel is selected which is unoccupied. A single speech channel is used for both transmission directions, which is enabled by time division and time compression. The degree of time compression is adjustable in response to whether speech signals are present for transmission or not. The equipment radio transmitters are adapted for either sending digital or analogue speech signals. The equipment radio receivers are adapted for operation according to the homodyne principle.</p> |
