| 摘要 |
<p>PURPOSE:To detect a change in state accurately by sampling and storing a signal which varies with time, sampling and storing the stored value, and detecting the presence of a difference by comparing both the stored value with each other. CONSTITUTION:When a switch 1 is turned on, an output Vi is amplified by an amplifier 3 and a sampling gate (SG)4 turns on with a pulse T1 to charge a capacitor (C)5 to a voltage VC1; and then a switch 14 is closed to charge C7 to an initial value voltage VC2. With a pulse T2, a comparison gate 9 turns on to make a comparison 8 between the voltages of Cs 5 and 7, and when they have no difference, an output V0 is not generated. With a pulse T3, an SG6 turns on to transfer the potential of C5 to C7. If Vi varies, SG4 turns on with the pulse T1 and the comparison gate 9 turns on with the pulse T2, and consequently there is a difference generated between inputs to a comparator 8 to generate the output V0; and a plunger 11 is driven by a driver 12 and the switch 1 is turned off. Thus, a change in state is detected accurately and this circuit is suitable for the tape end detection of a tape recorder.</p> |
