Frequency Response of Phase Locked Loops

This paper is concerned with the design of the phase locked loop (PLL) to be used as an FM demodulator. With the introduction of the PLL IC and the trend of designing inductorless circuits, there has been much interest in the PLL FM demodulator.1'2 The discussion in this paper concentrates on the steady state response of the PLL to sinusoidally frequency modulated signals;. therefore, the analytic and experimental results are shown in the form of frequency response diagrams.