Patent ID: 6731919
Filing Date: 2004-05-04
Classification: H04B

Abstract:
An amplifier apparatus, the amplifier apparatus being adapted to convert a signal to be processed into one having an intermediate frequency band to thereby execute amplification processing, comprising:a local oscillator the oscillation frequency of that can be altered; a first frequency converter that converts the signal to be processed by the use of the oscillation frequency from the local oscillator into an intermediate frequency; a first intermediate frequency band/band pass filter that limits to an intermediate frequency band the signal to be processed having the intermediate frequency that has been output from the first frequency converter; an intermediate-frequency amplifier that amplifies the signal to be processed having the intermediate frequency that has passed through the first intermediate frequency band/band pass filter; a second intermediate frequency band/band pass filter that limits to an intermediate frequency band the signal to be processed having the intermediate frequency that has been output from the intermediate-frequency amplifier; a second frequency converter that converts the signal to be processed having the intermediate frequency that has passed through the second intermediate frequency band/band pass filter into the original frequency by the use of the oscillation frequency from the local oscillator; a temperature sensor that detects the temperature of each of the first and second intermediate frequency band/band pass filters; and a controller that alters the oscillation frequency of the local oscillator in correspondence with the detected temperature and thereby stabilizes the transmission characteristic of each of the first and second intermediate frequency band/band pass filters irrespective of the change in the temperature.