Should be available in the Crystal Semiconductor data sheets.
Be warned that this sort of voodoo is easy on the surface, but very difficult to do right.
You'll need a clock source or-if you want a professional one- you'll need to extract a clock source from an incoming reference that will 'back-clock' your output (analogous to 'Genlocking' in Video operations) then you'll need an AES/SDIPF decoder, an AES/SPDIF encoder, the Sample Rate Converter ship itself, some means of instructing it as to what sample rate it is to outut to (most should be able to identify the incoming rate automatically).
The above is for ASRC (asynchronous sample rate conversion). If you want the synchronous variant (sometimes not useable: for example bringing 'wild' (unreferenced) digital source -a domestic CD player is a useable example- into a master referenced setup. The Synchronous variant is "easier" insofar as you divide or multiply the incoming clock by a fixed factor, and the reference is derived from the input.
Whoever said it's easy to build probably meant that you can just use the crystal semiconductor data sheets and about three of their chips together with some supporting/buffering/clocking circuitry.
Failing that, whoever told you it's "easy" either has some new definition of the word easy which I'm not familiar with, or they just need a slap! :twisted:
Keith
:?:
