Method and system for calibrating a crystal oscillator
US5892408A · kind A · utility
Inventor
Key dates
| Filing date | Feb 5, 1997 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Feb 5, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/2824
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and system are provided for calibrating a batch of devices each containing a circuit which is responsive to a control signal for producing a desired output which varies in accordance with a first predetermined function of a specific ambient condition, the control signal having a magnitude which varies as a second predetermined function of the specific ambient condition, the second function being based on data stored as a look-up table in a memory of the device and which must be individually calibrated for each device. In a preferred embodiment, the device is a digital temperature controlled crystal oscillator which produces a desired output frequency and includes a voltage controlled oscillator (VCO) responsive to a control signal having a magnitude which varies as a predetermined function of ambient temperature in order to compensate for temperature variations in the oscillator output frequency. For such an application, the invention requires the connection of an accurate frequency source to each oscillator in the batch so as to enable the output frequency of the oscillator to be equalized thereto or to a multiple thereof. In calibration mode, the digital equivalent of th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.