Beacon/Radar Video Generator System for Air Traffic Simulation, US4591858, 05/27/1986

Preprogrammed aircraft target information is stored in separate lists of beacon and radar target words each including azimuth, range and amplitude data for a designated target within the current one of a plurality of predetermined azimuth "half" sectors. For each radar target word whose starting and ending azimuth includes the current azimuth, its amplitude data is loaded into the range bin of one of a first pair of high speed RAM data stacks addressed by the range data of the target word. When the radar trigger occurs, the previously loaded data stack is read out sequentially bin-by-bin. An echo pulse is formed by a video data output control for each range bin containing a non-zero value. For a beacon target of valid azimuth, the amplitude data is loaded into the range bin of one of a second pair of data stacks addressed by the range data of the beacon target word. The same amplitude data is loaded into every eighth range bin for which the corresponding bit of the transponder 3/A or C code is a "1". The previously loaded stack beacon data is read out sequentially at a slightly faster rate for beacon targets than for radar targets to simulate the standard ATCRBS interpulse period. The data stacks for either beacon or radar targets are alternated so that one is available for loading while the other one is being read out.