External unit for use in subscriber side of transmission system, synchronizes local oscillator using reference subcarrier placed in transmission frequency band, by transposing transposed subcarrier into desired frequency span

摘要

A local oscillator (104) transposes a transmission frequency band placed with reference subcarrier, to transposed frequency band including transposed subcarrier. A synchronizing unit for synchronizing the local oscillator using the reference subcarrier, has selector (107) for transposing the transposed subcarrier into desired frequency span. An Independent claim is also included for radio frequency transmission system.