US Patent 7724170 Sensor interface devices and amplifiers

Disclosed are a sensor interface device and an amplifier used in a sensor system. The sensor interface device in one implementation has a first chopper configured to shift input signals of the sensor system from a baseband frequency to a first frequency, an instrumentation amplifier configured to amplify the shifted signals, a bandpass Delta-Sigma modulator configured to digitize the amplified signals, and a second chopper configured to shift the digitized signals from the a first frequency back to the baseband frequency. The instrumentation amplifier removes the DC offset generated from the first chopper and therefore all sources of DC offset are eliminated in this interface device without bandwidth limitation.