567 Tone Decoder The NE567 or SE567 is a Phase Locked Loop (PLL) Tone Decoder. It is highly stable with synchronous AM lock detection and power output circuitry. Its primary function is to drive a load whenever a sustained frequency within its detection band is present at the self-biased input. The bandwidth center frequency and output delay are independently determined by means of four external components. Wide frequency range (0.01 Hz to 500 kHz) Supply voltage: 5v typical High stability of center frequency Independently controllable bandwidth (up to 14pct) High out-band signal and noise rejection Logic-compatible output with 100mA current sinking capability Inherent immunity to false signals Frequency adjustment over a 20-to-1 range with an external resistor Touch-Tone decoding Carrier current remote controls Ultrasonic controls (remote TV, etc.) Communications paging Frequency monitoring and control Wireless intercom Precision oscillator Circuits using a 567 Tone Decoder.