Up & Over Sampling... Continued


I recently emailed Kevin Halverson of Muse Electronics and asked him for a short layman's description of the difference between digital over sampling and upsampling. Kevin designed the Muse Model Nine and two ninety six that are on Stereophile's Class A+ list, and he is one of the top digital designers in the business. His entire response of 08/11/00 follows: "Dear Craig; Over & upsampling are both Sample Rate Conversion processes (SRC). Both accomplish the same basic goal of increasing the sample rate to increase the image rejection. Neither has any inherent advantage over the other, assuming both are done in a synchronous and integer fashion. The basic differentiation is that upsampling is an external process, oversampling is an internal one. In the case of the Model Two Ninety Six or Model Nine, the internal rates are 352.8 kHz for CDs and either 354 or 768 kHz for DVDs. The present trend towards the use of "upsampling" devices is to improve the performance of poorer performing converters (those with inadequate image rejection). In the case of either the Two Ninety Six or the Model Nine, neither would benefit from any additional image rejection as both already have more than is necessary. I hope this will give you a small amount of insight to the process and all the marketing hype being thrown about. Best Regards, Kevin Halverson". Craig.
garfish
Jordan and Craig, thanks for your postings. You guys are great for sharing this information! Jeff Kalt's e-mail really helped "fill in the gaps" and I think I see where I was off in my earlier posting. Thanks again. -Tony
Craig, I saw that Kevin Halverson visited the Resolution CD thread and the "...Pepsi Challenge" thread. That is pretty cool of him to pop in and comment! Did you ask him to visit the site to help explain some of the thorny topics? If so, great job!! Keep livin' the good life! Jordan
Just came across a commentary by Kevin Halverson on the MUSE Web Site in their DOCUMENTS SECTION which I found EXTREMELY interesting and informative entitled -- Sample Rate Converters (up & oversamplers) & their use in Digital Audio CHECK IT OUT AT: http://www.museelectronics.com
I would also suggest reading dCS's white papers on the effects of Jitter and digital "Smearing" at http://www.dcsltd.co.uk/papers.htm Cheers