| Symmetrische Anordnungen | H03D 7/14 |
| Mehrfachfrequenzumsetzung | H03D 7/16 |
| Ausführungen von Frequenzumsetzern zum Beseitigen von Spiegelfrequenzen | H03D 7/18 |
| Mittels Laufzeitröhren | H03D 7/20 |
| Durch Ablenken eines Elektronenstrahls in einer Entladungsröhre | H03D 7/22 |
| Balanced arrangements | H03D 7/14 |
| Multiple-frequency-changing | H03D 7/16 |
| Modifications of frequency-changers for eliminating image frequencies | H03D 7/18 |
| By means of transit-time tubes | H03D 7/20 |
| By deflecting an electron beam in a discharge tube | H03D 7/22 |