The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 1991
Filed:
Mar. 08, 1990
Jere W Hohmann, Doylestown, PA (US);
Bruce J Rogers, Collegeville, PA (US);
Stephen A Ransom, Huntingdon Valley, PA (US);
Daniel M Clementi, Doylestown, PA (US);
Integrated Circuit Systems, Inc., Valley Forge, PA (US);
Abstract
A video dot clock generator includes a phase-locked loop (PLL) which includes a voltage controlled oscillator, a frequency divider, a phase comparator and a loop filter. The voltage controlled oscillator (VCO) is programmable to provide multiple frequency ranges for a given range of control voltages applied to the oscillator. The programming affects both the frequency range and the gain of the VCO. The phase comparator includes circuitry which simulates a predetermined minimum phase error which, when compensated for, substantially eliminates jitter in the dot clock signal. The frequency divider used in the PLL and a similar frequency divided used to generate the reference signals for the phase comparator are programmable via an internal memory which also holds programmable control signals for the VCO. The memory, in turn, may be programmed by the user to achieve desired frequency and loop again characteristics for a given application.