| 摘要 |
PURPOSE:To suppress the transmission of an undesired burst signal due to transient phenomenon at the interruption of the device power supply or at voltage drop by means of a simple circuit in a TDMA communication system by driving a switching circuit by an output of a NAND gate receiving an output of a detection means detecting the power supply voltage drop and a burst control signal. CONSTITUTION:A power voltage drop detection means 1 uses a voltage comparator 13 to compare a power voltage VE with a voltage division by a breeder circuit 11, and to give an output V1 as an L level for a prescribed time taudepending on a resistor and a capacitor 12 in the breeder circuit 11 and as an H level for other time. The NAND gate 2 receives a bust control signal Vb aud the output V1, and an output V2 of the gate 2 is at H with the output V1 set at L level regardless of the level (H or L) of the signal Vb. In a switching circuit 3 intermitting a burst signal output Vout turning on/off the burst signal input Vin by the output V2, the switching circuit 3 is turned on by the H level of the signal V2 to interrupt the input Vin and to make the output Vout zero.
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