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:
Jan. 06, 2004
Filed:
Mar. 19, 2002
Kazuaki Oishi, Kawasaki, JP;
Hideki Ishida, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A frequency measurement circuit comprises a plurality of frequency measurement units , K each of which counts a reference clock Cb during a counting period having a predetermined number of waves of an input signal Cin, each of the frequency measurement units counts the reference clock, with shifted counting periods, respectively. Moreover, an adder is provided to add the counted numbers of the plurality of the frequency measurement units. By shift the counting periods, even if the phase of the input signal agrees with the phase of the reference clock at the time counting starts and at the time counting ends on a certain frequency measurement unit, there is scarcely any possibility of agreement of the phases on other frequency measurement units. Therefore, by utilization of the added number of counts, frequency can be measured with high accuracy. In addition, by making the counting periods being shifted with overlaping each other, extension of the measurement time is not required any longer.