Interferometer design using CMD297P34

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1

Hi there, Im looking to build an interferometer that uses the CMD297P34 to get two branches to be matched in phase - precision is of the utmost importanct. A few questions:

  1. What type of phase shifter is this? mems based, ferroelectric or varactor based?
  2. whats the phase error with analog voltage input? What specs do you reccomend for the analog control voltage?
    3.On page 8 of the datasheet, for the Vctrl pin there is a diode and capacitor in paralell. is this internal to the chip, or are these external components that you recommend?

Thanks!

2

The CMD297P34 is FET/varactor based. The datasheet does not give a phase error/accuracy. The part is specified to meet a certain phase shift range with 0V to 10V control voltage. It can be used to give a relative phase shift, but not accuracy for an absolute phase shift for a particular control voltage. The diode and capacitor shown for control pin 18 are a diagrammatic representation of the internal circuit attached to that pin. Hope this answers your questions.