Digital rate conversion with a non-rational ratio for high speed echo-cancellation modem

The application of digital rate conversion in high-speed echo cancellation modems is discussed. The requirement of rate conversion in echo cancellation modems is first described. The author then introduces the concept of digital rate conversion with a nonrational ratio and considers two types of approximations for implementation of such a rate converter. Special considerations for the application of rate conversion to echo cancellation modems are discussed in detail. The design requirements and optimization criterion of interpolation filters for this application are discussed. The special problem of sampling clock jitter occurring in this application, its impact on modem performance, and its compensation techniques are discussed.<>