Resonators for the microcomputer compensated crystal oscillator

The goal of the resonator development program discussed by the authors was to develop dual c-mode resonators which have: frequency vs. temperature (f vs. T) characteristics free of significant anomalies; the minimum possible f vs. T slopes for the temperature ranges of interest; high Q; and small hysteresis. Well-behaved dual c-mode SC-cut resonator designs have been successfully developed. Plano-convex resonators of the proper contour are shown to be well-behaved on both the third overtone, at 10 MHz, and on the fundamental mode over at least a -55°C to +85°C temperature range. Such resonators are shown to be suitable for microcomputer compensated crystal oscillators with a stability of a few parts in 10⁸