The 567 FM demodulator circuit

The figure illustrates the 567 FM demodulator circuit. The FM signal is received at pin 3, while the demodulated output signal is available at pin 5. The central frequency of the FM signal that the circuit can demodulate is given by the formula: fo = 1.1 / (R * C). In this circuit, C1 serves as the filtering capacitor, and C2 is the wideband adjustment capacitor. As C2 is decreased, the bandwidth of the circuit also reduces.

The 567 FM demodulator is a versatile integrated circuit designed for demodulating frequency-modulated (FM) signals. The circuit operates by utilizing phase-locked loop (PLL) techniques to extract the original audio or data signal from the modulated carrier wave. The central frequency, fo, which can be demodulated, is influenced by the values of the resistor (R) and capacitor (C) in the circuit, allowing for flexibility in tuning the circuit to different frequencies.

Pin 3 is designated for the input of the FM signal, which is then processed by the internal circuitry of the 567. The demodulated output signal can be accessed at pin 5, providing a clean representation of the original modulating signal. The filtering capacitor C1 is crucial in smoothing out the output signal, reducing noise and ensuring a clearer audio or data output.

Capacitor C2 plays a significant role in adjusting the bandwidth of the demodulator. By altering the value of C2, the user can modify the frequency response of the circuit, allowing for optimal performance depending on the characteristics of the incoming FM signal. A decrease in C2 results in a narrower bandwidth, which can enhance selectivity in environments with multiple overlapping signals. Conversely, increasing C2 broadens the bandwidth, which may be beneficial for receiving signals with a wider frequency deviation.

The 567 FM demodulator circuit is commonly used in various applications, including radio receivers, communication systems, and other electronic devices that require reliable FM signal demodulation. Its design emphasizes simplicity and effectiveness, making it a popular choice among engineers and hobbyists alike.In the figure is the 567 FM demodulator circuit. In the figure, the FM signal is input from 3-pin and the demodulated signal is output from 5-pin. The central frequency of the FM signal that the circuit can demodulate is: fo=1.1/RC. In the circuit, C1 is the filtering capacitor, C2 is the wide band adjusting capacitor, when C2 is going down, the band width o.. 🔗 External reference