Issued Patents All Time
Showing 1–9 of 9 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4480229 | Amplifier arrangement with parallel-operated amplifier sections | Theodorus J. Van Kessel, by Friedrich J. de Haan, administrator | 1984-10-30 |
| 4399328 | Direction and frequency independent column of electro-acoustic transducers | by Friedrich J. de Haan, administrator | 1983-08-16 |
| 4395588 | MFB system with a by-pass network | Friedrich J. de Haan, administrator, Adrianus J. M. Kaizer, Cornelis A. M. Wesche | 1983-07-26 |
| 4375623 | Arrangement for the transmission of audio signals | by Friedrich J. de Haan, administrator, Kornelis A. Immink, Eise C. Dijkmans, Mathias H. Geelen | 1983-03-01 |
| 4366346 | Artificial reverberation apparatus | Eise C. Dijkmans, by Friedrich J. de Haan, administrator | 1982-12-28 |
| 4361727 | Sound reproducing arrangement for artificial reverberation | by Friedrich J. de Haan, administrator | 1982-11-30 |
| 4352954 | Artificial reverberation apparatus for audio frequency signals | by Friedrich J. de Haan, administrator | 1982-10-05 |
| 4321552 | Amplifier comprising a first and a second amplifier element | Gerardus A. van Maanen, Henricus G. J. M. Kockelmans | 1982-03-23 |
| 4221928 | Noise reduction circuit for stereo signals | Mathias H. Geelen | 1980-09-09 |