CD4046 is a Micropower Phase-Locked Loop (PLL) that comes with a phase detector for comparing the phase of the output signal with the input signal and adjust them in order to make the matching signals from both ends.
The input signal can be operated in two ways: capacitively layered with a self-biasing amplifier for creating a small voltage signal or directly coupled for a large voltage signal.
The chip features two phase comparators i.e. Phase Comparator I and Phase Comparator II. They are also known as Phase Detectors.