sinara-hw / Phaser

Quad channel 1GS/s RF generator card with dual IQ upconverter and dual 5MS/s ADC and FPGA in EEM form factor
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modifications for baseband outputs? #154

Open dhslichter opened 1 year ago

dhslichter commented 1 year ago

A few thoughts for possible modification @gkasprow

  1. change out the u.fl connectors for THT MMCX
  2. make footprints for the baseband version so that all baseband outputs can come out through THT MMCX immediately after reconstruction filter, rather than two of the four channels going first through the digital attenuators.

Item 1 improves connector robustness, enables more mating cycles, permits a much wider selection of cables to be used. I understand the tradeoff when using THT that it has more impact on the rest of the board layers.

Item 2 enables the four outputs to be matched in a nice way (length-matched, attenuation-matched) if they are being used to drive external IQ modulators for example. I would be OK leaving the option to send two of the four channels through the digital attenuators, basically by placing a jumper you can either go to the digital attenuators or out the THT MMCX right after the reconstruction filter.

Background for this is that we are planning to use baseband Phasers with external modulators, rather than upconverter Phasers, based on experience from Oxford in performance of the modulators. We will also be using baseband Phaser outputs directly for parametric modulation of trapping potentials, and there connector robustness/ability to choose different cables would be nice (if not essential).