Self calibrating crystal controlled frequency counter method and apparatus
US4215308A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1978 |
| Grant date | Jul 29, 1980 |
| Priority date | — |
| Expiry date | Oct 30, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/1071
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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 a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.