To All, >From my personal experience, I have seen over 10dB improvement from the 3rd harmonics onward if spread spectrum oscillator were used.
Regards Vi Lucent Technologies ---------- From: Knighten, Jim [SMTP:[email protected]] Sent: 09 July 1998 19:30 To: [email protected] Subject: RE: spread spectrum oscillator To All: Publications can be found in the open literature on IBM/Lexmark spread spectrum clocks. For those interested, the most recent that I am aware of is Keith Hardin, et. al., "Design Considerations of Phased-Locked Loop Systems for Spread Spectrum Clock Generation Compatibility," 1997 IEEE International Symposium on Electromagnetic Compatibility, August 1997, p. 302, Symposium Record I'm sure if you searched backwards in time you will find more. Jim ----------------------------------------------------------------------- - --------------------------- Dr. Jim Knighten NCR 17095 Via del Campo San Diego, CA 92127 Telephone: 619-485-2537 Fax: 619-485-3788 e-mail: [email protected] ---------- From: [email protected] [SMTP:[email protected]] Sent: Thursday, July 09, 1998 8:48 AM To: [email protected] Subject: RE: spread spectrum oscillator "Necessity is the mother of invention." From 1957 to 1991, IBM's Office Product Division operated out of Lexington KY. In 3/91 this division was sold and became Lexmark International. During the IBM years, the Lexington based products were at the bottom of the IBM product line in terms of function and pricing. During the mid-80's IBM Lexington began to develop products that required classical controller cards etc. However, we could not afford to use the more expensive means of EMI abatement such as multiple innerplanes on mother boards. Lexington's EMC personnel developed numerous techniques to maintain the use of non-innerplane processor boards, even for some of the early IBM PS/1 PCs which were engineered and manufactured here. Lexington ran several "Non-Innerplane" seminars for IBM's other labs to share the techniques that kept EMI costs to a minimum. During the early 90's several of our EMC engineers applied spread spectrum techniques to some of our product models, and subsequently patented some of these techniques. Various papers have been presented by our EMC people on this topic at EMC conferences. For more information, contact: Dr. Keith Hardin ([email protected]) John Fessler ([email protected]) George Alspaugh Product Safety (EMC manager 1981-1993) Please respond to "WOODS, RICHARD" <woods%[email protected]> To: emc-pstc%[email protected], "'Robert Walch'" <rwalch%[email protected]> cc: (bcc: George Alspaugh/Lex/Lexmark) bcc: George Alspaugh/Lex/Lexmark Subject: RE: spread spectrum oscillator Lexmark seems to think that there is a market. They have a patent in this area and have actively marketed the technology. Richard Woods Sensormatic Electronics [email protected] Views expressed by the author do not necessarily represent those of Sensormatic. > ---------- > From: Robert Walch[SMTP:[email protected]] > Reply To: Robert Walch > Sent: Wednesday, July 08, 1998 6:35 PM > To: [email protected] > Subject: spread spectrum oscillator > > We recently finished a design of a spread spectrum oscillator for a > major test equipment manufacture. I was wondering if there was a > general need for a spread spectrum oscillator. Does anyone have any > experience using or looking for such a device. Is this a technology > that is worth further development or should I just let it die? > > Rob Walch >
