| 摘要 |
Errors in digital transmission are monitored by employing a cyclical-redundancy-check (CRC). A CRC code word having a predetermined number of bits is generated (via 310) from a block of bits (ESF) of a presently transmitted time division muliplexed (XTDM) signal. The code word bits are then inserted (via 304, 305, 306) into predetermined bit positions of the next subsequent block of bits (ESF) of the XTDM signal. In a receiver (FIG. 7), bits of a presently received time division multiplexed (RTDM) signal are compared (801, 802) to bits of a CRC code word generated from the last previously received block of bits to indicate errors in transmission. In a specific example, a 6-bit CRC code word is employed and the code word bits are inserted into predetermined framing bit positions.
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