American Dynamics TMV910Q User Manual page 11

Triplex Digital Video Multiplexer
Unlike a quad processor, which records pages of several cameras each in real time but
with greatly reduced resolution (75% of the information is lost per image in a quad
view), the multiplexer records each image in the sequence encoded and sent to the
VCR at full resolution. This results in high definition reproduction of each video
image, but not in real time. This triplex multiplexer records a full 60 fields per second,
for minimal reduction in smoothness of motion. A multiplexer is usually considered
more satisfactory for most installations than a video switcher, which records one
camera at a time for a preset interval, allowing a significant gaps between recording
intervals for each camera, during which important information can be missed.
Figure 2 — Video Decoding
Technical Overview 3