Patent ID: 8433013

Claim:
A receiver for receiving a signal of a plurality of frequency bands simultaneously, the plurality of frequency bands including a frequency band of a desired channel and a frequency band of an adjacent channel adjacent to the desired channel, said receiver comprising: an oscillator for generating a local oscillator signal; a frequency converter for heterodyning the signal of the plurality of frequency bands into an intermediate frequency (IF) signals using the local oscillator signal; a filter connected to an output of the frequency converter, the filter having a variable cut-off frequency; an analog-digital (AD) converter connected to an output of the filter, the AD converter converting the signal of the plurality of frequency bands into a digital signal, the AD converter having a dynamic range; a pre-stage detector connected to an output of the AD converter or connected between the filter and the AD converter, the pre-stage detector detecting a signal level; and a controller for controlling the variable cut-off frequency of the filter based at least on the dynamic range and the signal level detected by the pre-stage detector to cause the variable cut-off frequency to be selectively at least a first cut-off frequency and a second cut off frequency, the first cut-off frequency defining a pass band passing the frequency band of the desired channel, the second cut-off frequency defining a pass band passing the frequency band of the adjacent channel, wherein the controller is operable to: maintain the variable cut-off frequency at least at the second cut-off frequency when the signal level detected by the pre-stage detector is lower than the dynamic range; and vary the variable cut-off frequency to the first cut-off frequency when the signal level detected by the pre-stage detector is higher than the dynamic range.