Voltage-controlled oscillator with ac coupling to produce highly accurate duty cycle square wave output
US6445253B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 2000 |
| Grant date | Sep 3, 2002 |
| Priority date | — |
| Expiry date | Dec 18, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0995
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.