| Acceleration Sensitivity Stabilization Techniques Under Random Vibration

As phase noise of any PLL based frequency synthesizer module is direct dependent on phase noise performance of reference source. Use of such modules in electronic warfare environment is limited by phase noise performance degradation under random vibration experienced. Hence for stabilizing the phase noise performance of reference source mounted inside unit under test (UUT) module is important for reduction of its G-sensitivity nature. G-sensitivity reduction is achieved in two phases in present article. It is very much dependent on its spatial location as well as stabilization techniques. The finest spatial location (center of gravity) for mounting position of reference source is determined by using structural analysis method. Performance stabilization is achieved by two different techniques i.e. Mechanical and Electrical [5].
i). Structural Analysis
UUT structural analysis needs to be done to find out center of gravity for mounting of reference source and trying to filter out UUT resonance out of random vibration frequency spectrum profile. It avoids magnification of UUT resonance pickups during testing of Phase noise performance with in vibration spectrum profile as shown in Fig. 7. From Fig. 7, it is observed that the standalone housing of UUT having self-resonance at 1.4 KHz. It demands further modifications (i.e. positional weight analysis, physical profile alteration etc.) in present UUT to filter out self-resonance out of random vibration profile.