Narrowband FM Demodulator with Carrier Detection

In FM demodulation applications where the bandwidth is less than one-tenth of the carrier frequency, an XR-567 can be used to detect the presence of the carrier signal. When no carrier is present, the output of the XR-567 turns off the FM demodulator, thereby acting as a noise control function. In the circuit shown in the figure, the XR-215 FM demodulator features wide dynamic range, high signal/noise ratio and low distortion. When the frequency reaches 500kHz, the XR-567 detects the presence of a carrier wave.