Daniel A Allen

US Patent:

6522365, Feb 18, 2003

Filed:

Jan 27, 2000

Appl. No.:

09/491761

Inventors:

Vladimir Levantovsky - North Andover MA
Daniel J. Allen - Derry NH

Assignee:

Oak Technology, Inc. - Sunnyvale CA

International Classification:

H04N 506

US Classification:

348537, 348536, 348541, 348572

Abstract:

A method of recovering a pixel clock for generating a digital image from an analog video signal is presented. The on and off-transition times for the active video portion of a digital image and the image size defined in a video standard are used to generate a pixel clock. The analog video signal is digitized according to the pixel clock and the image size of the resulting digital image is compared with the image size defined in the video standard. The pixel clock frequency is adjusted in response to the image size comparison. The optimum phase of the pixel clock relative to the analog video signal is determined through a repetitive phase adjustment technique. A first image coordinate is determined for a pixel clock at one phase and a subsequent image coordinate is determined for a pixel clock after decrementing the phase of the pixel clock. The first image coordinate and the subsequent image are compared. If the coordinates are not equal, the steps of decrementing the phase of the pixel clock and determining a corresponding image coordinate are repeated until equal coordinates are determined.