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.