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:
Jul. 29, 1980
Filed:
Oct. 30, 1978
John A Kusters, San Jose, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method and apparatus for obtaining an accurate measure of the frequency of an applied signal by generating a pair of independent frequency signals wherein one of the independent frequency signals has a frequency value which is indicative of the operating temperature of the counter. The counter has two modes of operation: a calibration mode and a measurement mode. In the calibration mode, an accurate signal having a preselected frequency value is applied to the counter. The frequency of this signal is measured with reference to the other of the pair of independent frequency signals and this measured value is then algebraically combined with a prestored value that is equivalent to the preselected frequency of the applied signals. The combined value represents the necessary normalized correction factor for any measured frequency when the counter is at the corresponding temperature. The value of the one of the independent frequency signals in this mode serves as a pointer to the memory location where this correction factor is to be stored. This procedure is then repeated several times as the temperature environment of the counter varies. In the measurement mode an unknown signal is applied to the counter, its frequency value is measured against the other of the independent frequency signals, the value of the one of the independent frequency signals is utilized as a pointer to the necessary correction factor at the then operating temperature of the counter, the measured frequency value is corrected algebraically with this correction factor, and the final result outputted for further use by the user.