Simultaneous Measurement of Oscillator Amplitude and Phase Noise using Phase Detector based EPLL

This paper presents an Enhanced Phase Locked Loop (EPLL) used for an oscillator noise measurement. The EPLL has two feedback loops: phase locked loop (PLL) for phase estimation and amplitude locked loop (ALL) for amplitude estimation. The presented method also used for estimating fundamental signals along with phase noise and amplitude noise simultaneously. The EPLL is compared to the PLL technique by comparing mathematical analysis, simulation and measurement data. In mathematical analysis, the differential equation-based dynamic expression is derived from the circuit. This is followed by a circuit simulation, whose results were found to be close with the measured results for 100 MHz operations. Measurement results demonstrate that in steady-state EPLL shows less phase noise especially at close offset frequencies and comparable phase noise at higher frequencies when compared with conventional PLL.