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:
Nov. 20, 2001
Filed:
Mar. 27, 2000
James Roberge, Lincoln, MA (US);
Robert Joseph Ledoux, Harvard, MA (US);
Raymond Paul Boisseau, Waltham, MA (US);
William Philip Nett, Waltham, MA (US);
Applied Materials, Inc., Santa Clara, CA (US);
Abstract
A method and apparatus for generating an accurate, table phase shift (b) in a sinusoidal signal employs fast analog multiplication to implement the trigonometric relationship sin(&ohgr;t+b)=sin(&ohgr;t)cos(b)+cos(&ohgr;t)sin(b). Cos (&ohgr;t) is generated by accurately shifting a signal sin(&ohgr;t) through 90° using a delay line, for example. Sin(b) and cos(b) are dc signals generated by digital to analogue conversion, using a demanded phase shift (b) whose sine and cosine are obtained from look-up tables. A controller for controlling a phase shift in an rf cavity is also disclosed and operates on the basis of the same trigonometrical principle. The amplitude of the signals in the rf cavity is also controllable; fast analogue multipliers are again employed to scale the signal amplitude to a nominal fixed value such as 1 volt.