| 摘要 |
<p>An instrument (20) includes multiple sensing elements (6a, 6b, 6c, 6d) of the variable-capacitance type. The sensing elements are placed by a switching network (22) into a single capacitance sensing circuit (8); and those elements which are not active in the circuit at a given time are switched by another or the same switching network into a ground shunt (24). Preferably, all switching occurs at a ground state, and the sensing circuit briefly samples a sensing signal between successive switching operations, so that the sensed signal is uncorrupted by stray capacitance effects. The switching is effected at a rate, in relation to the expected vibrational spectrum of the sensor system, to determine a set of readings which are essentially equivalent to a set of simultaneous capacitance measurements of the plural sensing elements. A preferred system is a wight sensing system employing three or four load cells to support a scale platform.</p> |
