Principles of designing digital compensating accelerometers
Abstract
Digital compensating accelerometers use three types of feedback: (1) analog feedback with voltage-to-code or current-to-code conversion; (2) pulse-current conversion; pulse-current feedback; or (3) mechanical feedback through mass and strings. An accelerometer with voltage-to-code conversion, consists of a sensor, a position transducer, and amplifier which also converts the amplified signal to feedback current, an analog-to-digital converter shunted by a precision resistor, and a compensating current-to-force or current-to-torque converter. An accelerometer with current-to-code conversion includes, a reversible counter, a pulse generator, a current stabilizer, and a threshold device, all in parallel between two switches feeding into the feedback loop with an integrating capacitor across. In an accelerometer with a mass suspended betwen two orthogonal pairs of strings, the mass is the sensing element and the vibration frequency differences of the strings are the basis for compensation. Accelerometers with pulse-current feedback have a modulator behind a plain signal amplifier and a low-leakage transistor switch between the modulator and the compensating converter, this switch is also connected to a current stabilizer. The accuracy of the accelerometers is determined only by the error of the compensating converter, the instability and the nonlinearity of the current stabilizer, and the quality of the transistor switch.
- Publication:
-
USSR Rept Eng Equipment JPRS UEQ
- Pub Date:
- May 1985
- Bibcode:
- 1985RpEE........95S
- Keywords:
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- Accelerometers;
- Compensators;
- Electric Generators;
- Feedback;
- Parametric Frequency Converters;
- Analog To Digital Converters;
- Design Analysis;
- Error Analysis;
- Measuring Instruments;
- Instrumentation and Photography