Voltage-controlled oscillator with ac coupling to produce highly accurate duty cycle square wave output

Abstract

A voltage-controlled oscillator circuit includes a ring oscillator circuit for generating a signal having a series of pulses. The signal with the series of pulses is ac coupled to a filter circuit which converts the series of pulses into a substantially sinusoidal signal which is substantially symmetrical about the reference potential of the system. The sinusoidal signal is applied to an amplifier which converts the sinusoidal signal into a square wave. Because the square wave is generated as an amplified sine wave, it exhibits a high degree of symmetry, i.e., it has a highly accurate 50-50 duty cycle, which makes it applicable in demanding settings such as serving as a clock signal in a high-speed microprocessor system in which both rising and falling edges of the clock signal are used to synchronize events.

Dependencies are inferred from the claim text.