SYNCHRONISM DETECTING CIRCUIT

摘要

PURPOSE:To obtain plural synchronizing signals with a simple circuit by adding plural detection signals which are respectively generated at different time then identifying respectively the signals. CONSTITUTION:Light emitting elements 6-1-6-n, and photodetectors 8-1-8-n form respectively detectors and the quantity of the light of the respective light emitting element are in the relation 6-1>6-2>->6-n. The detection signals from the respective photodetecting elements are supplied to an amplifier 9 and are added. The output from the amplifier 9 is supplied to comparators 12-1-12-n of which the reference voltages are respectively different. The adjacent outputs of the respective comparators are supplied respectively to EXOR circuits 22-1-22- n-1. Plural synchronizing signals are therefore taken out of the outputs from the comparator 12-1 and the respective EXOR circuits. The plural synchronizing signals are thus obtd. with the simple circuit. The level of the detection signal is changed but the similar effect is also obtainable by changing the polarity thereof.