System and method for synchronization tracking in an in-band modem

摘要

Processing the synchronization of an inband modem to detect sample slip conditions is disclosed. Decision logic reliably detects the sample slip condition while minimizing the number of false alarms.

主权项

1. A method for identifying a sample slip in the transmission channel of an in-band modem comprising:
receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame; correlating the received data bit with a reference signal; and identifying a sample slip based on the correlating, wherein the correlating comprises a two-stage search, wherein a first stage of the two-stage search comprises finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, and wherein a second stage of the two-stage search comprises finding the maximum correlation among the possible maximum correlations.