Patent ID: 8693594
Filing Date: 2014-04-08
Classification: H03G,H04L

Abstract:
1. A receiver comprising: an antenna that receives an RF signal; a low noise amplifier that amplifies the received RF signal and outputs the signal; a local oscillating circuit that outputs a local oscillation signal; a π/2 phase shifter that outputs a signal obtained by phase-shifting the local oscillation signal by π/2; a first mixer circuit that outputs a mixed signal of the signal outputted from the low noise amplifier and the local oscillation signal; a second mixer circuit that outputs a mixed signal of the signal outputted from the low noise amplifier and the signal outputted from the π/2 phase shifter; a first low-pass filter that filters the signal from the first mixer circuit to output a first signal; a second low-pass filter that filters the signal from the second mixer circuit to output a second signal; a first variable gain amplifier that amplifies the first signal to output a third signal, the first variable gain amplifier having a gain variable with a first set value; a second variable gain amplifier that amplifies the second signal to output a fourth signal, the second variable gain amplifier having a gain variable with a second set value; a first arithmetic circuit that calculates a first mean value of the third signal in a preset first measurement setting period; a second arithmetic circuit that calculates a second mean value of the fourth signal in the first measurement setting period; a control circuit that controls the first arithmetic circuit and the second arithmetic circuit, changes the first set value according to the first mean value, and changes the second set value according to the second mean value; and a demodulator that outputs a signal demodulated from the third signal and the fourth signal.