Vibration compensated crystal oscillator
US4891611A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 9, 1989 |
| Grant date | Jan 2, 1990 |
| Priority date | — |
| Expiry date | Mar 9, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In order to compensate for mechanical vibration that corrupts the RF output spectrum of a crystal oscillator, three accelerometers are mounted with the oscillator and aligned on mutually perpendicular axes. The outputs of the accelerometers are digitized and applied to adaptive transversal filters comprising a digital signal processor. The crystal oscillator is placed on a vibration table and its output is compared with an external frequency reference. The tap weights of the filters are then optimized so that the vibration components of the output spectrum of the oscillator are minimized. After the tap weights of the filters are determined and fixed, the filters provide vibration compensation for the oscillator. During operation of the crystal oscillator, the outputs of the filters are summed and applied to a varactor in the oscillator to compensate the output for the effects of mechanical vibration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.