| 摘要 |
Disclosed is a two-wire transmitter which transmits information over a pair of wires having an external supply connected thereto. The transmitter receives its power from the pair of wires and stores a portion of this power during spaced apart first time intervals. This stored power is used to excite an external sensor during second time intervals that are substantially shorter than the first time intervals and which lie between respective ones of the first time intervals. The excitation response from the sensor is sampled and held in synchronization with this excitation. A variable resistance device is included for insertion in series with the pair of wires. This device is responsive to the held excitation response from the sensor to allow a current representative thereof to flow through the pair of wires.
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