Title :
A 300-MHz digitally compensated SAW oscillator
Author :
Cowan, W.D. ; Slobodnik, A.J., Jr. ; Roberts, G.A. ; Silva, J.H.
Author_Institution :
Rome Air Dev. Center, Hanscom AFB, MA, USA
fDate :
5/1/1988 12:00:00 AM
Abstract :
A method for compensating for the inherent temperature sensitivity of surface-acoustic-wave (SAW) oscillators is described. Results for a 300-MHz digitally compensated SAW oscillator (DCSO) show a reduction of temperature-induced frequency variation from +or-125 parts per million to +or-1.4 parts per million over the temperature range of -23 to 75 degrees C. This is accomplished using simple digital circuitry and microprocessor control. The temperature-sensing scheme, using a SAW structure with two delay paths of different temperature sensitivity on the same AT-cut quartz substrate, virtually eliminates thermal resistance and time-constant problems. Advantages over ovenized systems include fast warmup; reduced size, weight, and power dissipation; low cost potential; and the ability to compensate for other sources of frequency drift.<>
Keywords :
crystal resonators; frequency control; surface acoustic wave devices; -23 to 75 degC; 300 MHz; AT-cut quartz substrate; SAW oscillator; digitally compensated; frequency drift; frequency variation; microprocessor control; temperature sensitivity; Circuits; Delay; Frequency; Microprocessors; Oscillators; Power dissipation; Surface acoustic waves; Temperature distribution; Temperature sensors; Thermal resistance;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
