LOW PHASE NOISE OCTAVE BANDWIDTH FREQUENCY SYNTHESIZER UNDER VIBRATION CONDITION

Abstract

A frequency synthesizer is an electronic device that translates one (or more) input base (reference) frequency to a number of output frequencies. It can be treated as a \black box" containing individual components or building blocks such as voltage- controlled oscillators (VCOs), frequency dividers, multipliers, mixers, and phase detectors, which, when properly connected, perform this translation function. Its structure is de ned by a system architecture that describes the organization and relationships among the individual components. Frequency synthesizer is a key component to virtually any Radio Frequency(RF) and communication and mon- itoring system, microwave test-and-measurement. Particular problems can occur for frequency synthesizers under vibration. This e ects can cause failures. Vi- bration e ects on frequency synthesizers can interfere with data links.Vibration increases phase noise in frequency synthesizers due to its e ect on crystal oscilla- tors which have a mechanical component. In this research the idea is to design a Low phase noise octave bandwidth fre- quency synthesizer which can work under vibration conditions.We are generating a range of frequencies between 4GHz to 8GHz. Phase noise is very important in the PLL synthesizer because it determines several factors of the device in which it is included. An indirect multiple PLL approach is used in this research. The phase noise that is generated at di erent points around the loop and depending on how it is generated and in which component it a ects the output in di erent ways.Thats why noise performance of each circuit block in the loop is observed while designing the synthesizer so that best noise performance is obtained. Measurements of the prototype synthesizers phase noise are made.Prototype is simulated and veri ed before fabricating. Finally module is fabricated and tested. All the results of simulation and testing are given in detail.