The primary application of SAW devices is in filters.  Applications in precision frequency control and timing are limited because the long term stability and temperature stability of the best bulk-acoustic-wave (BAW) devices are better than those of the best SAW devices.
	For BAW resonators, the plate thickness determines then fundamental-mode frequency.  For SAW resonators, the interdigital transducers' (IDT) spacings determine the frequency.  For quartz, a 300 MHz BAW resonator plate is 6 m thick.  A 2.6 GHz SAW resonator has 0.3 m IDT spacings, and can be produced by e-beam lithography.
	In SAW resonators, wave motion is concentrated at the surface of the crystal; motion decays exponentially with distance from surface; 90 to 95% of the energy is within one acoustic wavelength of the surface.
	In one-port SAW and BAW resonators, the static capacitance, C0, provides a low-impedance path that can mask out the desired resonance at high f's.  An external inductor is usually placed in parallel with C0 to "resonate out" C0.  In two-port SAW resonators, C0 does not shunt the motional arm of the equivalent circuit,  therefore, two-port SAW resonators are preferred in many applications.  See chapter 4 for phase noise comparisons with BAW devices.
	D. P. Morgan, Surface-Wave Devices for Signal Processing, Elsevier, 1985.
	D. P. Morgan, “History of SAW Devices,” Proc. 1998 IEEE Int’l Frequency Control Symp., pp. 439-460, 1998.
	F. S. Hickernell, ”Surface Acoustic Wave Technology - Macrosuccess through Microseisms," in Ultrasonic Instruments & Devices II, edited by R.N. Thurston, A. D. Pierce, vol. ed. E. Papadakis, Physical Acoustics Vol. XXIV, Academic Press, pp. 135-207, 1999.
	W. R. Shreve and P. S. Cross, "Surface Acoustic Waves and Resonators," in E. A. Gerber and A. Ballato, Precision Frequency Control, Vol. 1, pp. 119-145, Academic Press, 1985.
	R. S. Wagers, “Surface-Acoustic-Wave Filters,” and “SAW Bandpass and Bandstop Filters,” in E. A. Gerber and A. Ballato, Precision Frequency Control, Vol. 1, pp. 230-249, and pp. 257-266, Academic Press, 1985.