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:
Feb. 16, 1988
Filed:
Oct. 14, 1986
John L Addis, Beaverton, OR (US);
Patrick A Quinn, Aloha, OR (US);
Tektronix, Inc., Beaverton, OR (US);
Abstract
A DC level shift circuit includes a differential amplifier with a level shift stage. The level shift stage has two portions for transmitting the input signals forming the differential signal through the level shift stage. A current source transmits the input signals through the level shift stage. Transistors with impedances substantially equal to the current source impedances are cross coupled to each input terminal. Each transistor senses a distortion signal produced by the current source impedance at one terminal and produces in response a correction signal. The correction signal is then transmitted to the other input terminal to be summed with the distortion signal there to pass the input signals through the level shift stage without distortion. The DC level shift stage is also responsive to another correction signal generated by a feedback control stage to control the common mode voltage of the amplifier.