Universal control grid modulator
US4454430A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 19, 1982 |
| Grant date | Jun 12, 1984 |
| Priority date | — |
| Expiry date | May 19, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/691
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
High voltage FET's (field effect transistors) are used to modulate a traveling wave tube, which makes it possible to achieve fast rise, fall and delay chracteristics, and very long pulsewidths to CW because of their low drive requirements to maintain the on condition. The low and high voltage portions of the modulator are coupled via special transformers having only one or two turns for each winding on torroidal cores. Since such transformers are not adequate for long pulse widths, the gate to source capacitance of a high voltage FET is charged with a short pulse from one transformer and held there by a blocking diode until it is removed by the off drive. To obtain pulse widths all the way out to CW, a regeneration circuit is incorporated in the low voltage circuitry so that if the commanded on time goes beyond a maximum time, successive pulses are generated to maintain the voltage between gate and source of the on FET.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.