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. 21, 1989
Filed:
Feb. 25, 1988
Yoshitaka Abe, Kawasaki, JP;
Keiichi Murakami, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A frequency of a signal, particularly a frequency, partly varied as time passes, of a signal is counted in real time by producing a delay signal by delaying the signal as much as a predetermined time, detecting delayed zero-cross pulses from the delayed signal, detecting zero-cross pulses from the non-delayed signal, counting a first number of the delayed zero-cross pulses after the predetermined time is over, counting a second number of the zero-cross pulses during and after the predetermined time, producing a number difference between the first number and the second number by subtracting the first number from the second number and halving the number difference. The predetermined time is designated longer than a half period of the signal frequency to be counted. When the predetermined time is set long, the average frequency of the signal is counted, and when that is set short comparing with the partly varied interval of the signal frequency, the partly varied frequency of the signal is counted in real time.