Patent ID: 6980610
Filing Date: 2005-12-27
Classification: H03G

Abstract:
1. A wireless terminal device comprising: a variable gain amplifier receiving a received signal; a first level detecting circuit having a widely selected input voltage range and detecting a level of the received signal supplied to said variable gain amplifier, wherein the first level detecting circuit comprises a logarithmic amplifier; a converting circuit converting an output signal from said variable gain amplifier into a digital signal; a second level detecting circuit detecting a level of an input signal to said converting circuit or an output signal from said converting circuit; and a controlling circuit that (a) coarsely controls the gain of said variable gain amplifier based on an output of said first level detecting circuit and (b) finely controls the gain of said variable gain amplifier based on an output of said second level detecting circuit to thereby adjust the output signal from said variable gain amplifier such that the output signal from said variable gain amplifier falls within an input voltage range of the converting circuit, wherein said controlling circuit supplies power to said logarithmic amplifier at the start of an operation and stops or reduces the power supply to said logarithmic amplifier when a feedforward control is finished to thereby decrease current consumption.