The vibration-induced phase noise of a visco-elastically supported crystal resonator

The performance of a VHF crystal oscillator in the 100-MHz range is described under vibration and during acoustic noise excitation. The fifth-overtone resonator is supported on four massive posts and held in place by a precisely controlled support area of a compliant adhesive. Because the adhesive is an insulator, electrical connections between crystal and header pins are made via Au-bonded wires. The behavior of the short-term stability, composed of near-carrier phase noise and of spurious, flexure-induced resonances experienced under typical vibration and acoustic noise stresses, is reported. Phase noise measurements obtained at X-band after ≈100× multiplication are described on a number of randomly selected SC and some At-cut crystals using the compliant mount. All results were obtained using the same foamed hybrid test oscillator excited with sinusoidal excitation of 2 g _rms at 1 KHz. These crystals routinely yielded a vibration sensitivity factor Γ⩽3×10^-10