The analog output card took digital data from the display system and turned that into analog signals for driving a CRT. Yup back then these things still used CRTs.
I had just completed the C17 design so it will come as no surprise that the V22 card was a very similar design to the C17 card. The interface to the digital system was via programmable logic devices (CPLDS) and these interfaces to some DACs. The output of the DACs was a current and this was turned into a voltage and then buffered off the card using amplifiers.
It's a pretty simple set up but if course the design had to be resilient and military spec to survive the extremes in temperature, vibration and other environmental concerns.