Differential termination and attenuator network for a measurement probe

摘要

A differential termination and attenuator network receives a differential input signal having a DC common mode voltage. The network circuit includes first and second input termination resistors coupled in parallel with corresponding resistive attenuator circuits. A monitoring circuit coupled to input nodes of the network generates an output signal representative of the combination of a DC common mode voltage on the input nodes and an applied termination voltage. A control circuit receives the output signal from the monitoring circuit and the applied termination voltage and generates a scaled termination voltage and a scaled compensation voltage and drive currents. The scaled termination and compensation voltages and drive currents provide DC currents through the input termination resistances and the attenuators for nulling DC currents at the network input nodes and provides a DC common mode voltage output from the first and second attenuators for optimizing the dynamic range of a differential measurement amplifier.