Fsk demodulator circuit

1. Which circuit is used in FSK demodulator?
2. How does FSK demodulator work?
3. How IC 565 is used to design FSK demodulator?

Which circuit is used in FSK demodulator?

The most used demodulation technique is the one using a PLL circuit (fig. 2). The FSK signal across the PLL input takes two frequency values. The error voltage supplied by the phase comparator follows such variations, and so, it constitutes the NRZ binary representation (high and low level) of the FSK input signal.

How does FSK demodulator work?

The FSK signal input is given to the two mixers with local oscillator circuits. These two are connected to two band pass filters. These combinations act as demodulators and the decision circuit chooses which output is more likely and selects it from any one of the detectors.

How IC 565 is used to design FSK demodulator?

FSK demodulator using NE-SE 565 IC

A very useful application of the 565 PLL is as a FSK demodulator. In the 565 PLL the frequency shift is usually accomplished by driving a VCO with the binary data signal so that the two resulting frequencies correspond to the logic 0 and logic 1 states of the binary data signal.