Oscillator temperature compensating circuit using stored and calculated values
US4922212A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 1989 |
| Grant date | May 1, 1990 |
| Priority date | — |
| Expiry date | Jun 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/026
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A voltage-controlled oscillator includes a compensating signal value calculator which calculates the value of a function representing the portion of the oscillator temperature-frequency transfer curve corresponding to the ambient temperature. A signal corresponding to the calculated value is then applied to the voltage-controlled oscillator as the control voltage. Basically, an oscillator temperature-frequency transfer curve is partitioned into n segments. For each segment an offset value, x.sub.n, equal to the difference between the frequency at the start of the segment and the desired frequency, is stored in a look-up table. When a compensating signal value is required, the compensating signal value calculator retrieves from the look-up table the x.sub.n values corresponding to the segment immediately preceding and succeeding segment k, segments "k-1" and "k+1". The retrieved values are labeled x.sub.k, x.sub.k-1, and x.sub.k+1, respectively. It then calculates a function representing the portion of the transfer curve passing through three points corresponding to the values: ##EQU1## The compensating signal value is then calculated by substituting the actual delta T value into th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.