| 摘要 |
A detection circuit for a position sensor comprises drive circuitry (3) connected to two impedance elements (1a, 1b) having an impedance which varies in dependence on the position of a movable member, so as to provide an oscillating signal dependent on the position of the movable member. A demodulator (4, 5, 6, 8, 13, 14) is provided for synchronously demodulating the oscillating signal to provide an output signal indicative of the position of the movable member. The demodulator includes sampling circuitry (4, 5, 13) for sampling the oscillating signal over two defined sampling periods in each cycle of the oscillating signal and for providing a sample voltage output which varies with variation in the impedance due to a change in the position of the movable member. The demodulator additionally includes a comparator (8) for comparing the voltages of the samples obtained over said sampling periods in each cycle, as well as a timing control device (6) for controlling the timing of the sampling in dependence on the result of the comparison so as to ensure that the sample voltage output varies in synchronism with variation in the impedance. |
