| 摘要 |
<p>A carrier detection circuit includes a rectification stage, an integrator, a comparator, and a digital counter. By utilizing a digital counter, long time constants are provided without the use of external components. If desired, a mark detect circuit is used when a mark must be present to signify the presence of carrier. Hystersis is provided by the comparator to insure that slight fluctuations in the carrier level do not affect the comparison.</p> |
