For a frequency output sensor, Honeywell produces the Accelerex RBA500 accelerometer. It is primarily used to supplement GPS navigation systems. It is a good choice where frequency output, high-g, small size, low power, and light weight are necessary.
The acceleration is measured as the frequency difference between two vibrating quartz beams. The output of the RBA500 is also thermally compensated using an internal temperature sensor and Honeywell-supplied coefficients; when integrated over time, delta Velocity is directly provided to the user’s system.