| 摘要 |
<p>Radio units are proposed having an enclosure containing a radio transmitter, a radio receiver and a processor for communicating with mobile terminals via the transmitter and the receiver and with a switching centre via an uplink data port and a transmission line having a nominal impedance. It is further proposed to provide a downlink data port connected directly by at least one pair of conductors to the uplink data port so that two or more radio units can be daisy chained together. A downlink port of a first radio unit would be connected to an uplink port of a second radio unit, so that the second can communicate with the switching centre via the first The invention is based on the recognition that at the end of the daisy chain, the at least one pair of conductors needs to be terminated in the nominal impedance of the transmission line or reflections will occur. It is desired that all radio units should be identical, in the sense that there is no desire to have a special radio unit to terminate a transmission line. The last radio unit in the chain, being most remote in the chain from the switching centre, is disclosed having connected to its downlink port an adapter connecting the conductors in the or each pair with an impedance having the nominal impedance of the transmission line. <IMAGE></p> |
