THE SCREEN

The program displays four planes: (1) an impulse-response graph, (2) a frequency-response graph, (3) a complex frequency plane for roots, and (4) a seismic data plane (such as a gather or section). Planes (1), (2), and (3) are line drawings or ``vector plots," and they update immediately, whereas plane (4) is a variable brightness plane that updates only on command and after a delay of several seconds.