This circuit has the ability to launch a 15kHz modulated light. The first level of 4001 for a single pulse generator can be manually key output detection pulses, for fault repair. In order to stabilize the modulated optical signal frequency, the circuit used in the divider CD4060 . It comes with an external crystal oscillator, internal multiple stage divider. For 1M crystal, after the 4060 Six frequency, frequency stability 151625kHz the square wave, and then zoom through the power FET current, you can drive hundreds of light-emitting diode at the same time luminous.