Burkhard Markmann

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Seelze, DE

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Patents Grantslast 30 patents

Information Patent Grant
Sound reproduction device with active noise compensation
- Patent number 5,949,897
- Issue date Sep 7, 1999
- Sennheiser Electronic KG
- Volker Bartels
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Sound reproduction device with active noise compensation
- Patent number 5,809,156
- Issue date Sep 15, 1998
- Sennheiser Electronic KG
- Volker Bartels
- H04 - ELECTRIC COMMUNICATION TECHNIQUE