| 摘要 |
PURPOSE: A relay having changeable bandwidth is provided to control a middle frequency of a bandwidth passing filter unit electrically by using a mixer connected with a local oscillator to enable controlling in direct or remote control. CONSTITUTION: In the relay for cellular phone comprises an uplink for amplifying a signal toward a base station, a downlink for amplifying a signal toward cellular phone, and a plural parallel amplifier chain is formed in the two links, at least one parallel amplifier chain includes a filter having a bandwidth passing filter unit connected in series. At least two bandwidth passing filter unit has a passing controllable bandwidth partly overlapped and a central frequency of two band passing filter unit is controllable for the overlap bandwidth to be changeable.
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