4-37
0
-20
-40
-60
-80
-100
-120
-140
-160
10-1
100
101
102
103
104
105
106
500 MHz x 20
100 MHz x 100
BAW and SAW
5 MHz x 2000
BAW
Offset frequency in Hz
L(f) in dBc / Hz
Vibration induced phase noise dominates the phase
noise of both (whichever has lower acceleration
sensitivity will have lower phase noise; currently,
BAW can provide lower sensitivity than SAW.)
Illustration assumes 1 x 10-9/g acceleration
sensitivity for both BAW and SAW, and 0.01
g2 / Hz random vibration power spectral
density at all vibration frequencies
Low-Noise SAW and BAW Multiplied to 10 GHz
(in a vibrating environment)
   The solid line shows the phase noises under vibration for both BAW and SAW oscillators.  The dotted lines show the phase noises without vibration.  In the presence of vibration, it is the acceleration sensitivity that determines the phase noise.  As is illustrated above, if the BAW and SAW oscillators have equal acceleration sensitivities, then, after multiplication to 10 GHz, they will have equal phase noise levels (up to about 10 kHz from the carrier).
   Acceleration sensitivity is discussed later in this chapter. See, especially, the notes under “Vibration-Induced Sidebands - After Frequency Multiplication”.


R. L. Filler, "The Acceleration Sensitivity of Quartz Crystal Oscillators:  A Review," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 35, No. 3, pp. 297-305, May 1988.