Patent ID: 6112070
Filing Date: 2000-08-29
Classification: H03J,H04B

Abstract:
A high frequency receiving circuit for a mobile and/or portable communication apparatus capable of receiving a desired signal within the band of a channel selected from a plurality of channels which are divided within a receiving band by means of frequency division based on selective channel information comprising:a first band limiter which attenuates the component outside the receiving band of a receiving wave received through an antenna by a predetermined attenuation value with respect to the component within said receiving band;a second band limiter which varies its passing band width to include said selected channel band and attenuates the component outside said passing band of the receiving wave outputted from said first band limiter by a predetermined attenuation value with respect to the component within said passing band;a local carrier wave generator which generates, based on said selective channel information, a local carrier wave of which the frequency is different from the center frequency of said selected channel by an intermediate frequency as set in advance; anda frequency converter which mixes the receiving wave outputted from said second band limiter with said local carrier wave outputted from said local carrier wave generator, thereby converting the center frequency of said desired signal contained in said receiving wave to said intermediate frequency.