Apparatus for controlling timing of signal pulses

US5789958A · kind A · utility

Assignee

• Credence Systems Corporation · US

Inventors

• Douglas J. Chapman · Lake Oswego, US
• Jeffrey D. Currin · Pleasanton, US
• Philip Theodore Kuglin · Tualatin, US

Key dates

• Filing date: Jan 13, 1997
• Grant date: Aug 4, 1998
• Expiry date: Jan 13, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F1/04
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A timing signal generator adjustably times successive pulses of an output timing signal. The generator receives input data before each output pulse and controls the timing of that output pulse in accordance with the input data. The generator includes a circuit providing a set of 2N phase signals frequency locked to a reference clock signal but evenly distributed in phase. First and second selectors each sample the data once during each cycle of the clock signal. The sampled data tells the first selector whether it is to produce a first output signal during the next clock signal cycle and, if so, which of the first N phase signals the first selector is to select for controlling timing of edges of the first output signal. The sampled data also tells the second selector whether it is to produce a second output signal during a next clock signal cycle and, if so, which of the second N phase signals the second selector is to select for controlling the second output signal. The first and second output signals are logically ORed to produce the timing signal. The timing of data sampling by each selector is separately adjusted so that the selector output signal changes state only when the se…