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:
May. 07, 2002
Filed:
Jan. 23, 2001
Koji Suzuki, Fukuoka, JP;
Masamichi Inenaga, Fukuoka, JP;
Kabushiki Kaisha Yaskawa Denki, Fukuoka, JP;
Abstract
An absolute encoder that can generate an absolute value signal by performing simple operation processing. Phase signals &phgr; to &phgr; are represented by j-bit digital signals, a signal b provided by dividing the phase signal &phgr; by 2 (where K is an integer) is subtracted from a phase difference signal &phgr; =c, an absolute value signal A =f of the number of pitches (a a ) with a signal of the high-order K bits of the signal provided by subtracting the signal from &phgr; as high-order bits and &phgr; as low-order bits, subsequently a signal g provided by dividing the phase signal A =f by 2 (where K is an integer) is subtracted from a phase difference signal &phgr; =h, an absolute value signal A =k of the number of pitches (a −a ) with a signal of the high-order K bits of the signal provided by subtracting the signal from &phgr; as high-order bits and f as low-order bits, and the process is executed in order, whereby a longer-pitch absolute value signal is generated and signals are processed in order from the shorter-pitch signals to the longer-pitch signals, whereby the condition under which the pitch number cannot be determined is eliminated, and a large allowance of a phase error between slits can be taken. An error of a phase difference signal at the high-speed scale rotation time can also be corrected and adjusted by PLL.