Our Rohde & Schwarz UPD Audio Analyzer, performs practically on all types of audio measurement, from frequency response measurements through to externally controlled sweeps with reference traces, determination of 3rd-order difference frequency distortion, spectral display of demodulated wow and flutter signals, etc. In contrast to many other audio analyzers, Rohde & Schwarz UPD, Audio Analyzer, is capable of performing real dual-channel measurements in the audio-frequency range, ie: there is no need for switchover between two inputs and this type of measurement is not limited to a few special cases. This unit was calibrated September 2008