| 摘要 |
A transducer bridge amplifier system includes a first operational amplifier having positive and negative inputs connected, respectively, to first and second output nodes of the bridge. The output of the operational amplifier is connected to a third node of the transducer bridge. A transducer of the transducer bridge is connected between the second node and the third node. A second operational amplifier has its positive input connected to ground and its negative input connected to the first node. A feedback resistor is coupled between the output of the second amplifier and a negative input of the second amplifier. An output signal produced by the second operational amplifier has a linear response to transducer deviation and low sensitivity to offset voltages of the first and second operational amplifiers. In a second alternate embodiment of the invention, the second operational amplifier has its output and its negative input connected to a negative terminal of a voltage supply biasing the transducer bridge amplifier system. The second operational amplifier has its positive input connected to the first node. The current flowing into the bridge system via the first node has linear response to transducer deviation and low sensitivity to affect voltages of the first and second operational amplifiers substantially independently of any impedance connected to the first node. In a third embodiment of the invention, the second operational amplifier can be omitted. A constant current source, rather than a constant voltage source, is used to bias the transducer bridge amplifier system. The current flowing into the first node biases linear response to transducer deviation and low sensitivity to offset voltage of the first operational amplifier.
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