Calculation of clock skew using measured jitter buffer depth

摘要

A system and method to measure the clock skew between transmitting and receiving devices operating with independent clock sources over a packet network is described. To provide adaptive playout in an IP telephony device without a sequencing scheme in the packets, the clock skew is measured and recorded. Using a PCM resampler that is implemented with an interpolation filter bank of FIR subfilters, the change in depth of the playout buffer during transmission is analyzed, and this change infers the clock rate associated with the transmission.