ET A School Radar Display – AN/SPA-25G Radar Indicator Group Practice Test

The signal in question is a write-enable control for the radar video memory. RDV, with a NOT, is used as an active-low write strobe to the 1A2A7A10 Radar Memory and TV Timing Card. When this inverted RDV signal goes active (low) at the correct video-timing instant, the received radar video data present on the data bus is written into memory. This gating ensures that each valid video sample is stored in memory in sync with the video timing, so the memory can later be read out for display.

This function is specifically about capturing and storing the incoming video data, not about adjusting brightness or synchronizing frames, and not about reading data from memory. The write path is what RDV (NOT) controls.