Quartz accelerometers with frequency output have been designed and built using etched double-ended tuning fork technology. These devices consist of two tuning forks connected in a cantilever beam configuration with beryllium-copper spacers which serves as a proof mass and inboard spacer. The frequency outputs of each tuning fork resonant circuit are mixed to yield an output frequency of approximately 1kHz at zero acceleration. The sensitivity of the devices is approximately 1Hz/G. The fundamental vibration frequency of the cantilever beam is 2200Hz in this undamped device. Shock testing up to 1500G has indicated good survivability characteristics. Individual fork measurements compared with assembled cantilevers tested in a +- 1G field in the temperature range of -55C to +85C indicate that residual stesses associated with assembly contributes to the temperature sensitivity of the bias frequency. Centrifuge testing has been conducted over the range of 0-120G with an indicated non-linearity of less than 2mG. (ERA citation 11:041471)
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