Double-mode excitation of quartz crystals without dips of activity on the C and B modes

Summary form only given. Doubly-rotated cut quartz resonators excited on the main C-mode and the thermosensitive B-mode simultaneously appear to be the most promising way for essential improvement of the basic performance of MCXOs and temperature sensors. This article elucidates the physical origins of the phenomena and searches for an effective method of designing double-mode resonators for improved operation. Careful exploration of the frequency spectrum of the fundamental mode and the 3d overtone SC-cut crystals while ambient temperature changes, allows one to identify spurious mode interactions with the B-mode. Furthermore, the dependence of the interaction intensity on the “energy trapping” in the crystal plate has been revealed and explained. The C-mode activity showed no noticeable fluctuations within the temperature range of -40 to +70 °C, while the B-mode activity deviated within 30 per cent for the fundamental mode and within 10 per cent for the 3d overtone crystals