Temperature compensation for a disciplined frequency standard
US4839613A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1988 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | May 31, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A disciplined frequency standard includes an adaptive control loop to correct for ambient temperature effects. The crystal resonator of the disciplined frequency standard is enclosed within an oven which is heated by current applied through a resistive heater. A small current sensing resistor is inserted in series between the oven current source and the oven heater to produce a voltage drop which is proportional to oven current. An analog temperature signal T is derived from the voltage drop and is multiplied with a frequency/temperature parameter dF/dT to produce a compound temperature correction factor UT. The frequency/temperature parameter U and an aging drift parameter B are measured in control loops which are weighted by averaging time parameters K, L, respectively. The measured values of B, U are stored and the weighting factors K, L are adjusted according to the variance of the most recent measurement from the stored average. The adjusted values of the correction parameters follow closely and converge to the actual parameters values over a period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.