| 摘要 |
<P>PROBLEM TO BE SOLVED: To filter base-band signals to improve reliability in wireless communication. <P>SOLUTION: As a technique for noise reduction in a wireless communication system, the present invention uses controllable bandwidth filters 120 to filter a received signal. The filters 120 are used at baseband frequencies. A measurement (RSSI) is indicative of the strength of the received signal. A filter control circuit 144 generates a control signal 146 to control the bandwidth of the filters 120. If the received signal strength is above a first threshold, a wider bandwidth may be used for the filters 120. If the received signal strength is below a second threshold, the filter control circuit 144 generates the control signal 146 to set the filters 120 to a narrower bandwidth. The bandwidth of the filter changes according to the presence of narrowband interference (disturibing signals) and an adjustable delay unit ensures constant group delays among all possible configurations of the filter. <P>COPYRIGHT: (C)2012,JPO&INPIT |
