Patent ID: 7282993
Filing Date: 2007-10-16
Classification: H03F

Abstract:
1. A frequency characteristics-variable amplifying circuit comprising: a pair of resonant circuits, each of which is connected between a first potential and a second potential, and has an inductor and a variable capacitor which forms a resonant section with said inductor; a pair of output terminals, each of which outputs an output signal from corresponding resonant circuit; and a pair of switch sections, one of said switch sections switching on and off between one of said resonant circuit and said first potential or said second potential based on one of complementary signals inputted to said switch sections to make said one of said resonant circuit to output a high or low signal determined by said first potential or said second potential to said corresponding output terminal, and the other of said switch sections switching on and off between the other of said resonant circuit and said first potential or said second potential based on the other of complementary signals inputted to said switch sections to make said the other of resonant circuit to output a high or low signal determined by said first potential or said second potential to said corresponding output terminal, wherein amplified signals of said complementary signals are outputted to said pair of output terminals, and frequency characteristics at the time of amplification can be varied by adjusting the capacitance value of said variable capacitor.