Upconverting AFE Mezzanine

[hartytp]

Initial design notes for an upconveritng AFE mezzanine likely to be funded by Oxford:

• RF input from DAC: 50MHz to 500MHz
• Microwave output: 2.5GHz to 3.5GHz using LO at 3GHz
• 1 microwave output channel per mezzanine (2 DAC channels) using IQ mixer (2nd output SMA is DNP/blanked off on front panel)
• LO fed in through SMPs from Sayma RTM (can use either clock mezzanine, or external source fed to the clock SMA on Sayma/Baikal front panel). This will be a PECL square wave @~3GHz
• Inputs: space allowing we will have 3 paths, with resistor jumpers to select between
  • 2 x InAmps as Allaki
  • 2 x direct inputs to ADC as Allaki
  • 1 x demodulated input to ADC, using IQ mixer fed either into InAmp or direct to ADC, as Allaki
• Otherwise, design as close to Allaki as possible
• Codename TBD

We also considered using 90-deg hybrids + IQ mixers to have 1 microwave output per 1 DAC channel. This improves channel cost/density at the expense of flexibility. For the time being, we decided to go for improved flexibility.

Please post if you have any comments/questions.

[jordens]

Just as a sidenote: You also get twice the bandwidth for this type of IQ mixing.

[hartytp]

Now funded by Oxford. @sbourdeauducq @jordens do you want to suggest a codename?

[hartytp]

One other comment on the design: use a "nice" IQ mixer for this, meaning good isolation, balance, etc. (i.e. don't just pick the cheapest one...)

[sbourdeauducq]

Nanoga

[sbourdeauducq]

And great news about the funding!

[hartytp]

Wiki updated to include Nanoga. This issue is now defunct.