05631920 is referenced by 87 patents and cites 8 patents.

A clock circuit includes an oscillator for generating a reference frequency signal, and a spread spectrum clock generator cooperating with the oscillator, generating a spread spectrum clock output signal having a fundamental frequency and reduced amplitude EMI spectral components at harmonics of the fundamental frequency. The spread spectrum clock generator preferably includes a clock pulse generator for generating a series of clock pulses, and a spread spectrum modulator for frequency modulating the clock pulse generator to broaden and flatten amplitudes of EMI spectral components which would otherwise be produced by the clock pulse generator. The spread spectrum modulator frequency modulated the clock pulses with specific profiles of frequency deviation versus the period of the profile. The clock generator circuits are digital and may be reset to a starting condition to synchronize the spread spectrum clock. For a laser printhead, the clock is synchronized with the start-of-sweep signal, so that printing is not degraded.

Title
Spread spectrum clock generator
Application Number
160077
Publication Number
5631920
Application Date
April 20, 1995
Publication Date
May 20, 1997
Inventor
Keith B Hardin
Lexington
KY, US
Agent
John A Brady
Assignee
Lexmark International
KY, US
IPC
H03D 1/04
View Original Source