| 摘要 |
<p>An improvement in an apparatus which uses a carrier detection threshold level (42) for detecting a carrier signal modulated with binary data. The threshold level is dynamically changed and generally seeks a level above the background noise. The threshold level is maintained constant when the detected signal exceeds the threshold level. Evaluation means (20) is able to examine the detected signal to determine if it contains data or only noise and if it contains only noise a possible trapped condition is avoided by raising the threshold level to a level higher than the background noise.</p> |
