Method and apparatus for a crystal oscillator using piecewise linear odd symmetry temperature compensation
US5691671A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 12, 1996 |
| Grant date | Nov 25, 1997 |
| Priority date | — |
| Expiry date | Jul 12, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/028
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method for temperature compensating a crystal oscillator (16) which includes a plurality of operational amplifiers (18,20) being driven by a temperature-dependent diode signal (28). The amplifiers (18,20) all operate across the entire temperature range of the crystal oscillator (16). Each amplifier (18,20) is adjusted to provide an gain (34,40,42,44,46) having a piecewise linear signal having odd symmetry about an inflection temperature (38) of a Bechmann curve of a crystal oscillator (16). The gain, slope and clipping of each amplifier (18,20) is adjusted such that the amplifier gains (34,40,42,44,46), when summed over the entire temperature range, provide a compensation signal (30) proportional to the Bechmann curve. The compensation signal (30) is subsequently applied to a tuning circuit of the crystal oscillator (16) such that a temperature compensated output (32) is obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.