Instrumentation amplifiers with improved accuracy for the audio frequency range

In the field of accurate ac ratio and ac power measurements, it is often desirable to adapt differential voltages to the input voltage range of the usually ground-referred measurement system with accuracies in the order of μV / V. For such purposes an instrumentation amplifier (IA) was investigated to improve the common mode rejection and the gain flatness in the audio frequency range. The design of the IA is used to set up measurement systems for various applications such as wideband current transformer- and efficiency measurements in the frame of current European Metrology Programmes (EMRP).