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. 22, 1994
Filed:
Sep. 10, 1991
Mamoru Ohba, Hitachi, JP;
Mitsuru Watabe, Katsuta, JP;
Rika Minami, Hitachi, JP;
Sanshiro Obara, Ibaraki, JP;
Hitachi, Ltd., Chiyoda, JP;
Abstract
A digital pulse processing device is capable of selecting desired precision. The digital pulse processing device includes a counter group for counting pulses output from a pulse output device, the counter group having a plurality of counters A and B that can be separated from and coupled with each other, a mode control circuit for instructing separation and coupling of the counters A and B, and a control circuit for separating and coupling the counters A and B in accordance with the instruction of the mode control circuit. An overflow condition of the free-run counter B is detected using an overflow flag. Detection of an overflow is conducted by setting the flag when an overflow condition has occurred twice or more. The flag is reset by rewriting the state of the flag by a software. An overflow condition which has occurred for the first time is detected in the conventional manner and is treated as carry or borrow. A register is provided to hold the value of the counter B when a microcomputer reads in the counter B. In this way, even when .DELTA.A(i)=0, speed detection operation can be executed using the value of the counter B obtained synchronously with the counting of the counter A.