Micro-machined accelerometer with tilt compensation
First Claim
1. A transducer comprising,sensing means for generating a displacement signal of a mass from a reference position with respect to a support structure,first forward circuit means including high pass filter means responsive to said displacement signal for creating a high-pass filtered displacement signal and converting same to an output binary bit stream representative of said high-pass filtered displacement signal,second forward circuit means including low pass filter means responsive to said displacement signal for creating a low pass filtered displacement signal, and converting same to an output low frequency signal representative of said low pass filtered displacement signal,first feedback circuit means responsive to said output binary bit stream for generating a binary force on said mass in a direction tending to restore said mass to said reference position,second feedback circuit means responsive to said output low frequency signal for generating a low frequency force on said mass in a direction tending to restore said mass to said reference position,whereby said output binary bit stream is representative of a characteristic of motion of said support structure at frequencies passed by said high pass filter, andsaid output low frequency signal is representative of a characteristic of motion of said support structure at frequencies passed by said low pass filter.
1 Assignment
0 Petitions
Accused Products
Abstract
A spring-mass-support structure is arranged as an accelerometer with two electrostatic feedback loops so as to measure two components of acceleration. Two of such accelerometers are advantageously used on a submerged platform to determine the direction of a sound source in a body of water. One of such feedback loops of each accelerometer is used to measure low frequency gravitational acceleration applied to the platform as a result of the tilt of the platform due to the action of current and wave action of the water. The other of the feedback loops of each accelerometer measures sound wave induced acceleration on the platform. The gravitational acceleration of each accelerometer is used to compensate the higher frequency acceleration for the effect of tilt of the platform.
-
Citations
4 Claims
-
1. A transducer comprising,
sensing means for generating a displacement signal of a mass from a reference position with respect to a support structure, first forward circuit means including high pass filter means responsive to said displacement signal for creating a high-pass filtered displacement signal and converting same to an output binary bit stream representative of said high-pass filtered displacement signal, second forward circuit means including low pass filter means responsive to said displacement signal for creating a low pass filtered displacement signal, and converting same to an output low frequency signal representative of said low pass filtered displacement signal, first feedback circuit means responsive to said output binary bit stream for generating a binary force on said mass in a direction tending to restore said mass to said reference position, second feedback circuit means responsive to said output low frequency signal for generating a low frequency force on said mass in a direction tending to restore said mass to said reference position, whereby said output binary bit stream is representative of a characteristic of motion of said support structure at frequencies passed by said high pass filter, and said output low frequency signal is representative of a characteristic of motion of said support structure at frequencies passed by said low pass filter.
Specification