Patent ID: 7711395
Filing Date: 2010-05-04
Classification: H03F,H04B

Abstract:
1. A signal processing apparatus comprising: a mixer which is connected to an antenna circuit operable to receive a broadcast signal having a desired frequency in order to convert said broadcast signal into a predetermined intermediate-frequency signal or baseband signal; a local oscillator operable to generate a signal having a frequency corresponding to said broadcast signal; a buffer circuit operable to receive an output of said local oscillator to supply a local-oscillated signal to said mixer; a frequency divider operable to divide a frequency of an output of said local oscillator; a PLL circuit operable to operate in response to an output of said frequency divider so that said local oscillator output may have a predetermined frequency; an intermediate-frequency signal processing section operable to receive an output of said mixer to process the intermediate-frequency signal or the baseband signal; a reference current source operable to supply a constant current to said mixer, said local oscillator, said frequency divider, said PLL circuit, and said intermediate-frequency signal processing section; a bias current detection section operable to detect a current value of said reference current source; and a current control circuit operable to control current values of said mixer, said local oscillator, said frequency divider, said PLL circuit, and said intermediate-frequency signal processing section in accordance with an output of said bias current detection section.