Interspeech'2005 - Eurospeech

Lisbon, Portugal
September 4-8, 2005

A Two-Microphone Diversity System and its Application for Hands-Free Car Kits

Jürgen Freudenberger, Klaus Linhard

DaimlerChrysler AG, Ulm, Germany

In this paper we consider a two-channel diversity technique that combines the processed signals of two separate microphones. For in-car applications, this enables a better compromise for the microphone positions. The advantage of the proposed system is its insensitivity with respect to varying speaker sizes or local noise sources. To achieve this we choose the microphone position in that way that one microphone is optimum for a tall speaker, and the second one is suitable for a small speaker. For local noise sources we may apply a similar design to choose the microphone position in accordance with the location of the noise sources. A corresponding signal combiner has to tasks: compensation of phase shifts and weighting proportional to the signal strength. We propose solutions for both problems and demonstrate the effectiveness of diversity combining.

Full Paper

Bibliographic reference.  Freudenberger, Jürgen / Linhard, Klaus (2005): "A two-microphone diversity system and its application for hands-free car kits", In INTERSPEECH-2005, 2329-2332.