Vibration Induced Phase Noise in Quartz Oscillators

One of the most critical factors concerning modern applications, such as radar acquisition or communication systems, is phase noise. Phase noise is defined as the noise arising from the rapid, short term random phase fluctuations in a signal.  It is an undesirable noise characteristic that appears on the output signal of an oscillator and can affect a radar system’s capability to accurately acquire a target or affect the spectral integrity within a communication system. Many papers and publications in the public domain discuss phase noise, its effect on applications, and measurement techniques. What is often missed, and what this paper addresses, are the effects of mechanical acceleration (vibration) on the output signal noise of quartz-based oscillators.  Unfortunately, even the lowest noise oscillators are affected by these mechanical accelerations. Typical examples may include the random vibration within an aircraft fuselage or simple sinusoidal vibration of a cooling fan mounted in a telecommunication equipment rack.