ARRANGEMENT IN A COMMUNICATION SYSTEM

摘要

An apparatus transmits RF signals in two widely separated frequency bands. The RF signals in the two frequency bands have the same modulated bandwidth. The apparatus utilizes substantially the same radio communication apparatus structure as in a radio communication apparatus designed for only one frequency band. RF signals for one frequency band are obtained when a first frequency multiplier is connected, generating RF signals by multiplying VCO signals from a VCO by a factor k. The RF signals for the other frequency band are obtained from the VCO when the first frequency multiplier is not connected. When the first frequency multiplier is connected, the modulated bandwidth of the VCO signals will multiplied by the factor k. This is compensated in a phase locked loop by connecting a second frequency multiplier, having the same multiplication factor k, at the same time as the first multiplier is connected. The second multiplier affects the bandwidth of the modulated VCO signal so that it will be k times smaller. The bandwidth of the modulated VCO signal is then recreated by the first multiplier.