ON A FREQUENCY RESPONSE OF PLL FM DEMODULATORS IN THE PRESENCE OF FM SIGNALS

Dragiša Krstić and Andjelija Vasić

In this paper, PLL FM demodulator frequency characteristics are considered. Special attention is paid to the influence of the operational amplifier dominant pole on the demodulator transfer characteristic. In an effort to lessen the influence of the operational amplifier dominant pole, predistortion technique is applied to the total PLL FM demodulator transfer characteristic. It has been shown that this influence can be neglected under certain conditions. It has also been shown that predistortion applied to the total PLL FM demodulator transfer characteristic lessens the influence of the active filter parasitic capacitance.