Method and apparatus for measuring the duty cycle of a digital signal

US7333905B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• David William Boerstler · Round Rock, US
• Eskinder Hailu · Austin, US
• Jieming Qi · Austin, US

Key dates

• Filing date: May 16, 2006
• Grant date: Feb 19, 2008
• Expiry date: May 16, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/31726
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The disclosed methodology and apparatus measures the duty cycle of a clock signal. A variable duty cycle circuit receives a clock signal from a clock signal generator. The variable duty cycle circuit adjusts the duty cycle of the clock signal by an amount dependent on a duty cycle index value that it receives. The variable duty cycle circuit supplies a duty-cycle adjusted clock signal to a divider circuit. The apparatus sweeps the frequency of the clock signal from a starting value up to a maximum frequency above which the divider circuit fails. The apparatus then determines the duty cycle of the duty-cycle adjusted clock signal from the maximum frequency.