Patrick, Thank you so much. I didn¹t know how to look something like this up.
Much obliged! Ken Javor Phone: (256) 650-5261 From: Patrick <[email protected]> Reply-To: Patrick <[email protected]> Date: Mon, 1 Mar 2021 17:59:20 -0700 To: <[email protected]> Subject: Re: [PSES] Clock Jitter, Effect on Radiated Emission Spectrum Hi Ken this is a great topic! i did a quick search for ' clock driver' and found a data sheet from Renesas with stability specified over temperature range. i am attempting to attach a screen shot... On Mon, Mar 1, 2021, 12:57 PM Ken Javor <[email protected]> wrote: > If a clock had absolutely no jitter whatsoever, then any available bandwidth > would suffice to capture the peak amplitude at the fundamental and at any > harmonics. > > If a clock has enough jitter that the spectrum falls outside the measurement > bandwidth, then we are not guaranteed that the measurement captures the peak > amplitude, unless the measurement bandwidth simulates that of the victim > receiver protected by the emission limit. This is the principle of the > dithered clock, and why it was useful in protecting broadcast radio, but much > less so for broadcast television. > > I am trying to get at what bandwidth is necessary to encompass the jitter > spectrum of undithered clocks. Clearly this is a function of harmonic order, > but a sense of the typical jitter spec on a clock will suffice to compute what > I need. I have heard 50 ppm, but no attribution. Can anyone out there > corroborate or correct? > > Thank you, > > Ken Javor > Phone: (256) 650-5261 > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
