Vector network analyzer with independently tuned receivers characterizes frequency translation devices

Abstract

A Vector Network Analyzer is equipped with receivers for measuring a, b, aand band which can each be tuned to track either the RF signal (F) applied to the FTD or to the IF (F) produced by the FTD. Additional forward side and reverse side mixers are provided and are driven by the auxiliary LO for the FTD. The additional mixers can be located in the RF/IF path, such that there is a sequential double conversion of the RF/IF: one by the auxiliary LO followed by another conversion of those results by the main LO. The additional mixers could also be located it the LO path, such that the main LO is first converted to an image involving the auxiliary LO, and the RF/IF is then subsequently converted using that image as an 'artificial' LO. During a forward direction measurement of an FTD, the applied RF signal (F) is converted to the IF with the additional forward side mixers that feeds the receivers for aand b. This references the forward measurements to Fand allows the FTD's input reflection and forward conversion magnitude and phase to be determined. A companion reverse direction measurement is to set the swept RF source to Fof the FTD's output. The additional reverse side mixers convert Fback to Fso that receivers for aand bare at the same frequency at the FTD's input port. This references the reverse measurements to F. The FTD's output reflection and reverse conversion magnitude and phase can be determined.