ANTIC and CTIA together produce the graphics, up to a resolution of 320x192 pixels, sprites, scrolling in any direction, different graphic modes that can be mixed on the same screen, etc.
*ANTIC is dedicated to the preparation of the video signal. It is a true microprocessor; it has an instruction set, a program called "the display list", and data. The display list and the display data are written into RAM by the 6502 CPU/microprocessor. ANTIC retrieves this information from RAM using Direct Memory Access (DMA). It processes the higher-level instructions in the display list and translates these instructions into a real-time stream of simple instructions to CTIA.
*CTIA is a television interface chip. ANTIC directly controls most of CTIA's operations, but the 6502 CPU can be programmed to intercede and control some or all of CTIA's functions. CTIA converts the digital commands from ANTIC (or the 6502) into a video signal that goes to the TV set or monitor. CTIA also adds some factors of its own, such as colour values, sprites (players-missiles in Atari's vocabulary) graphics, and collision detection. Games ordinarily requiring 48 KiB of RAM or more to handle complicated animation can be done in 16 Kib of RAM on machines with sprites (players-missiles in Atari's vocabulary).