Abstract: In a cellular system, including at least one cell site located within a corresponding geographic sector, an apparatus and method provides for expanding cellular system capacity through subdivision of the geographic sector by use of a cell site transceiver and a remote site transceiver to extend said cell site to a remote location within said geographic sector. Each transceiver provides duplex operation and includes a cellular band transmitter and receiver portion for local communication with the cell site or remote site mobile units, as the case may be; and a link frequency transmitter and receiver portion for communicating cellular band information, after conversion to an appropriate baseband frequency, between the cell site and the remote site transceivers.

Abstract: A split band filtering scheme to reduce adjacent band interference in a communications network, such as a cellular mobile radio system, is disclosed. A repeater, interposed between a base or cell site and a mobile/portable radio, includes a down converter for converting a system operating frequency to a lower frequency signal. The lower frequency signal represents a communications band. The signal is presented to a split band filter having a narrow passband with steep skirts. The processed signal is coupled to an up converter where it is restored to the system operating frequency. In this way, the passband of the repeater is restricted to that of the desired communications band and adjacent band interference is reduced or eliminated.