QUADRATURE VOLTAGE CONTROLLED OSCILLATOR USING PARALLEL COUPLING OF SOURCE TERMINAL

摘要

PURPOSE: A quadrature voltage controlled oscillator using parallel coupling of a source terminal is provided to reduce the low frequency noise generated from plural coupling transistors by improving a structure of the quadrature voltage controlled oscillator. CONSTITUTION: A quadrature voltage controlled oscillator using parallel coupling of a source terminal includes the first delay cell(410) for outputting the first and the second inphase signals and the second delay cell(430) for outputting the first and the second orthogonal phase signals. The first delay cell includes the first differential voltage controlled oscillator(401) and the first and the second coupling transistors(MN41,MN42). The first differential voltage controlled oscillator is connected between a power source and the first current source. The first and the second coupling transistors are used for changing the first the intensity and the direction of the current of the second terminal to the third terminal according to the intensity of the first and the second orthogonal phase signals. The second delay cell includes the second differential voltage controlled oscillator(403) and the third and the fourth coupling transistors(MN43,MN44). The second differential voltage controlled oscillator is connected between the power source and the second current source. The third and the fourth coupling transistors are used for changing the first the intensity and the direction of the current of the second terminal to the third terminal according to the intensity of the first and the second inphase signals.