| 摘要 |
<p>PURPOSE:To facilitate detection of collision by receiving a reference signal from a central station, allowing each terminal station to control the transmission level, and making the signal level from each terminal station at the head end uniform. CONSTITUTION:A signal Sti sent out from any terminal station Ti is sent to a central station through an up-circuit and returned through a down-circuit and received by receivers 20, 22 of the terminal station Ti together with the reference signal Sr, and the output level of a transmitter 28 is controlled according to the result of comparison of a comparator 24. By this way, when signals Sti, Stj are sent from two terminal stations Ti, Tj (not shown in the figure) and collision occurs, detection of the collision becomes easy as the level of signals Sti, Stj in terminal stations Ti, Tj can be made nearly equal.</p> |
