Patent ID: 7266352
Filing Date: 2007-09-04
Classification: H04B

Abstract:
1. A receiver circuit for down-converting a radio frequency (RF) signal, comprising: an RF mixer that down-converts an RF signal to an intermediate frequency (IF) signal; a first variable frequency RF local oscillator that supplies a first RF local oscillator frequency to the RF mixer; an IF mixer that down-converts the IF signal to a baseband signal; a variable frequency IF local oscillator that supplies an IF local oscillator frequency to the IF mixer, the IF local oscillator frequency being variable independently of variations of the first RF local oscillator frequency; a local oscillator control circuit that sets the first RF local oscillator frequency and the IF local oscillator frequency in accordance with an RF channel to be down-converted; and a second variable frequency RF local oscillator that supplies a second RF local oscillator frequency to the RF mixer; wherein the IF local oscillator frequency is variable independent of variations of the second RF local oscillator frequency; and wherein the local oscillator control circuit selectively controls the first variable frequency RF local oscillator and second variable frequency RF local oscillator to supply low-side RF local oscillator frequencies to the RF mixer from the first variable frequency RF local oscillator or to supply high-side RF local oscillator frequencies to the RF mixer from the second variable frequency RF local oscillator.