| 摘要 |
FIELD: physics.SUBSTANCE: apparatus for digitising impedance, having a first (22, 122) and a second (24, 124) impedance element, also has a control signal generator (26, 30) for transmitting a first alternating-sign control signal (44) to the first impedance element (22, 122) and a second alternating-sign control signal (46) to the second impedance element (24, 124), an analogue-to-digital converter (ADC) (42, 142) which receives the resultant signal (41, 52, 141), which is a combination of signals formed when the first and second alternating-sign control signals (44,46) are transmitted to the first and second impedance elements; the first alternating-sign control signal (44) is phase shifted relative the second alternating-sign control signal (46) such that the resultant signal (41, 52, 141), which is transmitted and digitised in the ADC (42, 142), successively characterises the sum of the first and second impedances and the difference between the first and second impedances. The apparatus also has a signal splitter (56, 156A, 156B), which receives values read from the ADC (42, 142) and forms sum channel (58, 158A) and a difference channel (60, 160A) therefrom.EFFECT: high accuracy and shorter measurement time.5 cl, 5 dwg |
