3차 PLL 주파수합성기의 1/f 잡음 모델링에 관한 연구

Abstract

The phase noise of PLL frequency synthesizer brings about a distortion of the signal in communication systems.

In this thesis, the frequency synthesizer using the third-order PLL was designed in order to predict the phase noise.

With Lascari's method, a variation of phase noise was analyzed in accordance with offest frequency, and the aspect of the 1/f- noise which give rise to troubles in the low frequency band specially was analyzed.

Since it is difficult to analyze mathematically 1/f-noise in the third-order PLL, the concept of pseudo-damping factor was introduced to access easily the 1/f-noise variance.

A numerical formula of 1/f-noise variance was shown in the third-order PLL, which was compared with that of 1/f-noise variance in the second-order PLL.

From the simmulation result, it was known that 1/f-noise variance in the third-order PLL exhibited inferior to suppression characteristics of that in the second-order PLL because of its noise bandwidth and 1/f noise variance factor over the damping factor in the range of 0.707 and 1