Tone Decoder
General Description
The LM567 and LM567C are general purpose tone decoders
designed to provide a saturated transistor switch to ground
when an input signal is present within the passband. The
circuit consists of an I and Q detector driven by a voltage
controlled oscillator which determines the center frequency
of the decoder. External components are used to indepen-
dently set center frequency, bandwidth and output delay.
Features
. 20 to 1 frequency range with an external resistor
. Logic compatible output with 100 mA current sinking
capability
. Bandwidth adjustable from 0 to 14%
. High rejection of out of band signals and noise
. Immunity to false signals
. Highly stable center frequency
. Center frequency adjustable from 0.01 Hz to 500 kHz
Applications
. Touch tone decoding
. Precision oscillator
. Frequency monitoring and control
. Wide band FSK demodulation
. Ultrasonic controls
. Carrier current remote controls
. Communications paging decoders