The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 15, 1980
Filed:
Mar. 13, 1978
Richard Morcom, London, GB;
Hughes Microelectronics Limited, Fife, GB;
Abstract
A device for providing a selectively variable proportion of an electrical signal, which can be used instead of a conventional resistive track potentiometer, is disclosed. The device comprises two switching devices, typically CMOS transmission gates, connected in series between two inputs for receiving the electrical signal, an output at the series connection of the switching devices, and a control circuit for cyclically switching the switching devices between high and low conductivity states. The control circuit is so arranged that when one of the switching devices is in its high conductivity state, the other is in its low state and vice versa, and the control circuit is arranged to control selectively the relative durations that the devices remain in their different conductivity states. A filter is connected to the output and in use, the output signal from the filter is of the same general waveform as the signal applied to the inputs but of a magnitude determined by the selected relative durations of the high and low conductivity states, determined by the control circuit.