Patent ID: 8934858
Filing Date: 2015-01-13
Classification: H03D,H03G,H04L

Abstract:
1. A digital demodulation circuit comprising: a variable gain control amplifier which amplifies a received signal of an intermediate frequency; an orthogonal demodulator which converts the received signal, amplified by the variable gain control amplifier, into a baseband signal so as to separate it into a common-mode component and an orthogonal component; an A/D converter which converts the common-mode component and the orthogonal component of the baseband signal into digital signals; a gain control circuit which generates a first gain control voltage based on the digital signals; a temperature compensation circuit which generates and smoothes a pulse-width modulation signal, having a pulse width corresponding to ambient temperature, so as to add a predetermined gain and an offset, compensating for variations in ambient temperature, thereto, thus generating a temperature correction value; and an adder which adds the temperature correction value to the first gain control voltage so as to generate a second gain control voltage, wherein the variable gain control amplifier amplifies the received signal with a gain corresponding to the second gain control voltage.