Patent ID: 7970372

Claim:
A frequency converter circuit that frequency-converts a first position signal, a second position signal and a third position signal, which are different from each other in carrier frequency and received from artificial satellites used in a satellite positioning system, the frequency converter circuit comprising: an oscillation signal generating section for generating a first local oscillation signal of a frequency that is set so that a frequency of the first position signal has an image relationship with frequencies of the second position signal and the third position signal, with respect to the frequency of the first oscillation signal, and so that frequency bands of the respective position signals do not overlap after being frequency-converted; a first mixing section for mixing the first local oscillation signal with the first, second, and third position signals to frequency-convert the respective position signals into a first intermediate frequency; a frequency dividing section for dividing the first local oscillation signal into 1/m, in which m is an integer of 2 or larger, to generate a second local oscillation signal of a frequency that is set so that the frequency of the first position signal of the first intermediate frequency has an image relationship with the frequencies of the second position signal of the first intermediate frequency and the third position signal of the first intermediate frequency; a second mixing section for mixing the second local oscillation signal with the first, second, and third position signals of the first intermediate frequency to frequency-convert the respective position signals into a second intermediate frequency, separating the first position signal of the second intermediate frequency from the second position signal of the second intermediate frequency and the third position signal of the second intermediate frequency, while removing the interference of the first, second, and third position signals with each other, and independently outputting the first position signal, the second position signal and the third position signal of the second intermediate frequency; and a separating section for separating the second position signal of the second intermediate frequency and the third position signal of the second intermediate frequency from each other, and independently outputting the second position signal of the second intermediate frequency and the third position signal of the second intermediate frequency.