Access time per pixel in raster systems

Question

Considering the two raster systems along with the resolutions of 640 x 480 and 1280 x 1024.

a) How many pixels would be accessed per second in each of these systems by a display controller which refreshes the screen at the rate of 60 frames per second?

b) Determine the access time per pixel in each system?

Answer 1

a) As 60 frames are refreshed per second and each frame comprises of 640 x 480 pixels, access rate of such a system is (640 x 480) * 60 = 1.8432 x 107 pixels/second. Likewise, for 1280 x 1024 system, access rate comes out to be (1280 x 1024) * 60 = 7.86432 x 107 pixels/second.

b) In accordance with the definition of access rate, we know that access time per pixel must be 1/(access rate). Thus, the access time is about 54 nanoseconds/pixel for 640 x 480 systems, and access time is about 12.7 nanoseconds/pixel for 1280×1024 system.