Antimultipath communication by injecting tone into null in signal spectrum

US4675880A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventor

• Faramaz Davarian · Los Angeles, US

Key dates

• Filing date: May 2, 1985
• Grant date: Jun 23, 1987
• Expiry date: May 2, 2005

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B7/005
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

A transmitter for digital radio communication creates a null by balanced encoding of data modulated on an RF carrier, and inserts a calibration tone within the null. By having the calibration tone coincide in phase and frequency with the transmitted radio frequency output for coherent demodulation of data at the receiver where the tone calibration signal is extracted and used for multipath fading compensation.