Quadrature voltage controlled oscillator capable of varying a phase difference between an in-phase output signal and a quadrature output signal

摘要

Provided is a quadrature voltage controlled oscillator capable of varying a phase difference between an in-phase output signal and a quadrature output signal. The quadrature voltage controlled oscillator comprises a first voltage controlled oscillator, a second voltage controlled oscillator, a first amplifier, a second amplifier, a third amplifier, and a fourth amplifier. The first voltage controlled oscillator generates a first output and a second output. The second voltage controlled oscillator generates a third output and a fourth output. The first output is a positive in-phase signal, and the second output is a negative in-phase signal. The third output is a positive quadrature signal, and the fourth output is a negative quadrature signal. The first amplifier is controlled by a first current and drives the first output and the second output in response to the third output and the fourth output. The second amplifier is controlled by a second current and drives the first output and the second output in response to the third output and the fourth output. The third amplifier is controlled by a third current and drives the third output and the forth output in response to the first output and the second output. The fourth amplifier is controlled by a fourth current and drives the third output and the forth output in response to the first output and the second output.