| 摘要 |
A measuring circuit comprises a capacitive transducer 18, a frequency generator 10 for supplying an alternating carrier voltage, a quad diode demodulator 12 electrically connected to the generator 10 and to the transducer 18 such that the demodulator 12 generates an output signal representative of a parameter effecting the transducer 18 and a compensation network 16 connected to the frequency generator 10 for varying the amplitude of the carrier voltage oppositely to the amplitude changes in the output signal produced by compensatable errors of the demodulator and transducer. As shown the compensation network 16 comprises a ratiometre compensation circuit 24 and temperature compensation for the demodulator. Alternatively linearizing and temperature compensation in respect of the transducer may be applied to the generator (Fig. 3 not shown). <IMAGE> |
