Method of detecting the frequency deviation in digital communication transmissions

US5305347A · kind A · utility

Assignee

• Deutsche Aerospace AG · DE

Inventors

• Hansjorg Roschmann · Neu-Ulm, DE
• Walter Theisges · Westerstetten, DE
• Manfred Zoberbier · Hechingen, DE
• Achim Brakemeier · Ulm, DE
• Jürgen Lindner · Worms, DE
• Ralf Esprester · Blaustein, DE

Key dates

• Filing date: Jul 7, 1992
• Grant date: Apr 19, 1994
• Expiry date: Jul 7, 2012

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B7/01
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

The invention discloses a method of measuring the rough frequency deviation in digital communication transmissions with echo propagation, particularly in the short-wave domain. A repeatedly transmitted PN sequence serves as the preamble of a data block. This PN sequence is compressed at the receiving end in matched filters provided in each one of a plurality of simultaneous, frequency offset Doppler channels. The Doppler channel having the greatest amplitude in the quadrature signal is selected for a determination of the rough frequency deviation. To detect a pattern in the preamble, the quadrature signals are examined for similarities by an amplitude comparison or in a cross-correlation process.