Method and apparatus for measuring a low power signal

US6660991B2 · kind B2 · utility

Assignee

• AGILENT TECHNOLOGIES, INC. · US

Inventors

• Volker Brombacher · Remchingen, DE
• Fritz Bek · Remchingen, DE

Key dates

• Filing date: Mar 11, 2002
• Grant date: Dec 9, 2003
• Expiry date: Mar 11, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G01J1/46
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Low intensity light is incident upon a photodiode whose output is coupled to an integrator. The output of the integrator is coupled to an input of an A/D converter, whose output is coupled to a microprocessor, whose output is coupled to a filter. A second output of the microprocessor is coupled to a gate electrode of a FET to provide a reset signal to the FET to reset the integrator. The microprocessor compares the digital samples of the integrated signal from the A/D converter and, firstly, generates the reset signal if a sample is beyond a set limit, and, secondly, calculates delta values between adjacent samples and interpolates the delta values for the reset periods so as to provide a continuous data stream which can be filtered by a filter matched to the form of the original signal.