Patent attributes
A digital multimeter receives a primary signal including a small amplitude DC component and an induced AC noise component with a magnitude exceeding a magnitude of the DC component. A 100 MΩ input resistor may couple an primary signal to signal processing circuitry that attenuates and filters the primary signal, convert a unipolar signal to a differential signal, and provide the differential output signal to an analog to digital converter. The multimeter may be configurable to couple any one or more of multiple available feedback paths to provide a plurality of available gain-bandwidth configurations. The multimeter may include a second input configurable with two or more feedback path impedances. The multimeter may include a second stage filter, shared by the primary and shunt inputs, that provides additional filtering and converts the signal to a differential signal. The second stage filter may support two or more available impedance configurations.
