Why do the DS21372/DS2172 receive synchronizers sometimes lock to patterns other than the transmitted pattern in repetitive-pattern mode?
A4. When the DS21372 and DS2172 are used to generate repetitive patterns, the receiver only searches for a repeating pattern of the same length as the pattern being transmitted. It does not verify that the receive pattern exactly matches the transmit pattern. Once the device has received a pattern of equal length, synchronization is declared. The device will then count any deviations in the received pattern as bit errors. A received pattern of all zeros or all ones will cause the device to synchronize no matter which pattern length is being transmitted. Also, any receive pattern length that is an even divisor of the transmit pattern length will cause the device to synchronize. Consider the following examples that meet the criteria above.
