Demodulator for tamed frequency modulation transmission system - uses decision circuit providing bit values from theoretical formula

摘要

The demodulator has a frequency discriminator (2) receiving the phase modulated signal, phase and frequency slave circuits (50,5) and a decision circuit (6). The frequency discriminator (2) provides a signal representing the phase variations in the input signal, which is fed to the non-inverting input of an operational amplifier. The amplifier receives a filtered feedback signal at its inverting input. The amplifier output (8) is fed to the decision circuit (6) and to the phase and frequency slave circuits (50,5), which provides the second input for the decision circuit (6). The decision circuit (6) determines the values of the received bits using a theoretical formula.