The phase locked loop is a feedback system comprised of a phase comparator, a low pass filter and error amplifier in the forward signal path and a voltage-controlled oscillator (VC0) in the feedback path. The block diagram of a basic PLL system is shown. Perhaps the single most important point to realize when designing with the PLL is that it is a feedback system and, hence, is characterized mathematically by the same questions that apply to other, more conventional feedback systems. The paramet