| 摘要 |
<p>PURPOSE:To prevent out-of-frame by a simple circuit configuration, by using a current switching circuit, an RC time constant element, a limiter and a voltage comparing circuit. CONSTITUTION:A parallel circuit consisting of a resistance Rc and a capacitor C is provided on the collector of a transistor TR2 of a current switching circuit constituted of transistors TR1, TR2, and an output of the collector is provided to a negative (-) input terminal 30 of a voltage comparing circuit 33 through a limiter 26. When a burst error which is larger than reference voltage Vref applied to the base of the transistor TR2 is applied to the base of the transistor TR1, a collector current flows to the transistor TR2, and the capacitor C is charged. When the collector voltage of the transistor TR2 attains to threshold voltage of the voltage comparing circuit 33, a protecting output is generated from the voltage comparing circuit 33. In this case, even if the burst error annihilates, the protecting output is continued only for a period decided by a discharge time of an RC time constant element.</p> |
