Asynchronous Sampling Rate Conversions in Digital Communications Systems

The problem of resampling digital signals at an output sampling rate that is incommensurate with the input sampling rate is the topic of this paper. This problem is often encountered in practice, as for example in the multiplexing of video signals from different sources for the purpose of distribution. There are basically two approaches to resample the signals. Both approaches are thoroughly described and practical circuits for hardware implementation are provided. A comparison of the two circuits presented in the paper shows that one circuit requires a division to compute the new sampling times. This time scaling operation adds complexity to the implementation with no performance advantage over the other circuit, and makes the “division free” circuit the preferred one for resampling.