Crosstalk Suppression for Modulated Subcarrier Measurement Systems

A double modulation technique to reduce both low frequency crosstalk and RF-crosstalk in modulated measurement systems has been developed. The modulation concept uses two double balanced mixers as modulators, which are driven by appropriate signals to yield a high crosstalk suppression. The achieved crosstalk reduction when using the double modulation technique compared to a standard modulation technique is typically better than 25 dB. Measurement results demonstrating the effectiveness of the double modulation technique are presented.