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Phase matched cable assemblies

Question asked by RFItech on Nov 10, 2009
Latest reply on Nov 16, 2009 by Dr_joel

I was hoping to get some feed back from one of the mods about the settings after calibration for measuring cables that are phase equal within a specification tolerance.  I have the N5230A which I know will perform the task quite easily.  I have read several documents from the internet about how this is done but no one is detailed enough with their explanation concerning the settings on their analyzer.  Something I read in this forum said that you can attach a pigtailed cable and measure the delay.  I didn't know you can measure delay without attaching the other end of the cable to the test port unless you were in time domain.  I didn't think a time domain display of delay would be very accurate when one end of the DUT is open.  I thought measuring phase in an S21 display or time in a group delay display was a transmission measurement.

I would like some help with the overall setup.  The only way I know is to calibrate with a stepped sweep, 10ms per step, NOP = 401, IFBW @ 100 KHz, power @ +3dB or higher depending on the frequency span, attach the gold standard and save it into the memory and then compare the next cable using the math/memory and displaying mem/data.  I can use the phase offset function if the marker at the frequency of interest is somewhere near the + or - 180 degree scale division and set it as close to zero as possible, then I wouldn't need to use the mem/data function.  Does this explanation here sound close?  If someone can answer the statement about measuring pigtails without attaching the other end, that would be helpful also.  Thanks.