Oscillator free run frequency setting by data bus control
US5486866A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1994 |
| Grant date | Jan 23, 1996 |
| Priority date | — |
| Expiry date | Jun 21, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/126
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A free running frequency alignment method in a video display having a sync generator comprising a first oscillator having a first frequency and a second oscillator having a second frequency. The first oscillator is phase modulated by the second oscillator which has a free running frequency different from a standard frequency. The free running frequency of the first oscillator is to be controllably aligned to the standard frequency by a method comprising the steps of applying a frequency determining initial control value to the first oscillator and measuring an average free running frequency responsive to the initial control value. An absolute difference frequency is calculated between the average frequency and the standard frequency. The absolute difference frequency is tested for a frequency value less than a predetermined value which signifies an aligned condition. If the difference frequency is less than the predetermined value the alignment is complete. If the difference frequency is greater than the predetermined value the alignment is continued and a new control value is generated responsive to the difference. The new control value is applied to the first oscillator and the s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.