Low-noise microwave-frequency synthesisers - Design principles
Abstract
After recalling the basic phase-noise equation for a general second-order phase-lock loop (PLL) system, noise power spectral densities invariant to frequency multiplication or division (normalized h-representations) are introduced. This is done in order to ease the solution of frequency synthesizer noise problems and the graphic construction of the expected noise levels, while allowing the contributions of individual sources to be examined. It is theoretically and experimentally proved that the thermal noise generated in the low-pass loop filter dominates certain parts of the PLL noise characteristic. It is shown that the choice of third-order type-two PLL configurations is imperative for low-noise designs. The usefulness of the h-representations is demonstrated with two practical examples of an ultra-low noise microwave synthesizer and low-noise synthesizers for radar and microwave communications.
- Publication:
-
IEE Proceedings H: Microwaves Optics and Antennas
- Pub Date:
- December 1983
- Bibcode:
- 1983IPMOA.130..483K
- Keywords:
-
- Frequency Synthesizers;
- Low Noise;
- Microwave Oscillators;
- Network Synthesis;
- Phase Locked Systems;
- Design Analysis;
- Noise Prediction;
- Performance Prediction;
- Thermal Noise;
- Transfer Functions;
- Electronics and Electrical Engineering