Pulse width modulating circuit
US4118677A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1974 |
| Grant date | Oct 3, 1978 |
| Priority date | — |
| Expiry date | Dec 5, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C1/16
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A modulator includes an output tank circuit energized from a d.c. source through a switching tube and a coupling circuit. The grid of the switching tube is driven by signal-modulated variable width rectangular pulses. The resulting output pulses from the switching tube are used to shock excite the tank circuit and thus produce a carrier wave having an amplitude that varies in accordance with the rectangular pulse width. The trailing edges of the switching tube output pulses are rapidly reduced to zero level by means of an auxiliary circuit that provides spikes of cutoff voltage to the tube grid at the termination of each variable width rectangular pulse. The coupling circuit serves to maintain the anode of the switching tube at a substantially constant voltage level while the tube is conducting so as to provide highly efficient operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.