A New Approach to a High-Stability Temperature-Compensated Crystal Oscillator.
Abstract
The report describes a compensation approach based on the introduction of controlled nonlinearity into the TCXO's frequency-voltage tuning characteristic by using a pair of varactor diodes and a fixed bias source. The result is considerable simplification of the temperature-compensation process for a TCXO using a fundamental AT-cut crystal unit. The simplification comes about by transformation of portion of the classic cubic voltage correction function to a monotonic function which then can be approximated to a high degree of accuracy with one or two '3-point' network segments, using a given thermistor in each. A stability of plus or minus 5 x 10 to the minus 8th power (5 to 80C) was obtained in one case where the required monotonic compensation function was generated in two segments. In another example, a stability of plus or minus 1 x 10 to the minus 8th power was easily obtained by compensating over a plus or minus 10C range about the upper turnover temperature. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1970
- Accession Number
- AD0715955
Entities
People
- S. Schodowski
Organizations
- United States Army Communications-Electronics Command