Low cost signal reconstruction based testing of RF components using incoherent undersampling

Testing of radio frequency (RF) components such as mixers, amplifiers and voltage controlled oscillators (VCO) traditionally relies on the ability to accurately estimate the device characteristics using down conversion or undersampling based test setups. Efficient and accurate acquisition of the modulating signal either requires a phase locked local oscillator signal or is limited in accuracy. This makes the setup more complicated and hence costly. In this paper a novel low cost test setup, independent of the requirement of any phase synchronous local carrier, is proposed. The technique relies on the capability of estimating the carrier phase and frequency with a high accuracy through simple back end algorithm. The envelope and carrier waveforms of the DUT (10GHz mixer followed by buffer amplifiers) are reconstructed through back-end signal processing from samples acquired directly at the component output using incoherent undersampling. From the reconstructed test response critical performance parameters (AM-AM and AM-PM) of the DUT are computed.