Digital temperature compensated crystal oscillator
US5548252A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 7, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Dec 7, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/368
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital control system such as a digital temperature compensated crystal oscillator (DTCXO) system is arranged to offer superior oscillating performance with reduced size and cost. For example, to reduce the memory capacity, a memory 31 receives upper 6 bits of temperature data, and a decoder 32 calculates temperature compensation data from lower 4 bits and output data from the memory (FIGS. 1-11). For a one-chip configuration and low power consumption, a MOS type Colpitts oscillator (FIG. 16) is provided with a circuit for adjusting the source resistance of the MOS. For size reduction and fine frequency adjustment, a DTCXO is provided with sections such as an adder 341, an up-down counter 342 and an auxiliary frequency control section (AFC) 332 (FIGS. 20, 21, 24 and 25). An adding section 415 is provided between a D/A converting section 414 and a capacitance varying section 416 to obtain superior linearity with respect to a control voltage and quality of offset.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.