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. 25, 2003
Filed:
Oct. 24, 2001
Kazuya Takahashi, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A reference clock is inputted into a target IC from a reference clock generator, and an output signal whose frequency is minutely deviated is converted into binary digital output data by a digitizer to be stored in an area A of memory. A computing unit generates digital data having the same period as a reference clock to store the digital data in an area B of the memory. Ternary numeric data is obtained by subtracting data in the area B from data in the area A of the memory to be stored in an area C of the memory. Data in the area C is added to the numeric data every fixed time and is stored in an area D of the memory. An amplitude of a waveform of this data is proportional to the deviation amount of a frequency, and, a period thereof corresponds to one period of deviation amount of a frequency. It is possible to easily implement a test for a deviation amount and a period of a frequency by obtaining the relation between the amplitude and deviation amount beforehand.