A graphic display system has a frame buffer that is 640 pixels wide, 480…

CONCEPT

For a raster display, one complete frame requires accessing every pixel once. If a frame contains N pixels and each pixel takes t seconds to access, the frame time is T = N × t and the refresh rate is f = 1/T.

Color depth affects storage size, but it does not add another factor here because the problem already gives the access time per pixel.

APPLICATION

1. Count the pixels: N = 640 × 480 = 307,200 pixels.

2. Convert the access time: t = 200 nanoseconds = 200 × 10−9 seconds per pixel.

3. Find the frame time: T = 307,200 × 200 × 10⁻⁹ seconds = 0.06144 seconds.

4. Take the reciprocal: f = 1/0.06144 = 16.276… frames per second.

CROSS-CHECK

At 16 frames per second, one frame takes 1/16 = 0.0625 seconds, which is close to the calculated 0.06144 seconds; the small difference is due to approximation.

Therefore, the refresh rate is approximately 16 frames per second.