| 摘要 |
PURPOSE:To obtain secure reception level detection characteristics by processing a carrier signal from a transmitting station by three provided detectors differing in level. CONSTITUTION:Received carrier signal a inputted to terminal 10 is supplied to detecting circuits 1-3 differing in detection level. On the arrival of signal a, circuit 1 turns ON to output signal c to receiveing circuit 9. Circuits 2 and 3, so constituted that low carrier levels will be detected by steps, send their output signals d and f to differentiating circuits 4 and 5 respectively. Circuit 4 differentiates the rise of signal d to obtain pulse e, and circuit 5 the fall of signal f to obtain output pulse g. Signals e and g drive RSFF consisting of NAND circuits 6 and 7, output signal h controls AND circuit 8, and signal c is gated to obtain output signal i. Consequently, the output signal operates at its OFF-ON level with more level width than that of its ON-OFF level, and the carrier can be detected without exerting any influence on rising characteristics. |
