Patent ID: 6288619
Filing Date: 2001-09-11
Classification: H03C,H04L

Abstract:
A bias circuit for use in a quadrature modulator, said bias circuit having an input terminal supplied with an input signal through a low pass filter having an output impedance, said bias circuit having first and second nodes for producing a noninverted signal and an inverted signal, respectively, said bias circuit comprising:an input capacitor disposed between the input terminal and the first node;a first resistor disposed between a power supply terminal and the first node;a second resistor disposed between the power supply terminal and the second node;a third resistor disposed between the first node and a ground terminal;a fourth resistor disposed between the second node and the ground terminal;a ground capacitor disposed between the second node and the ground terminal; anda bias stabilizing resistor connected between the first and the second nodes, said bias stabilizing resistor having a resistance value which is substantially equal to an impedance value of the output impedance of said low pass filter.