Electronic heterodyning in an optical detector

US4156135A · kind A · utility

Assignee

• The United States of America as represented by the Secretary of the Army · US

Inventors

• Walter E. Miller, Jr. · Huntsville, US
• Robert R. Mitchell · Huntsville, US

Key dates

• Filing date: Nov 11, 1976
• Grant date: May 22, 1979
• Expiry date: Nov 11, 1996

Classification

• Technology area (CPC G): Physics
• CPC primary: G02F2/002
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical detector, being operated in a non-linear portion of its response urve, is used as an electronic heterodyning element for two applied frequencies. They may be applied with two modulated light sources, or one source and an alternating current bias component to provide a preselected sum or difference output signal for selectable input frequencies allowing optical tracking of a target.