| 摘要 |
<p>In a data transmission system data is sent, after suitable conversion, as a ternary analog type signal. Using two-wire twisted pairs and hybrids, echo cancellation and feedback equalization are needed. Synchronization between the two ends, e.g. of a 144 Kb/sec. subscriber's loop is maintained by a low amplitude pilot tone sent with the data, and detects at the same time as the data is detected. Detection and elimination of this pilot tone use coefficient generation circuitry similar to those used in the equalizer and echo canceller.</p> |
