function of quad and multiplexer?

[Sophie A 0]

what is the function of quad and multiplexer?

and what's the function of VCR?

[Soundy 1]

A quad takes up to four video signals and displays them as either a 2x2 split display, or cycles through them, or in some cases will do a picture-in-picture display (one camera full-screen, another in a small window).

 

A multiplexer performs the same function, plus processes video for output to a time-lapse VCR, and processes the video playback from the VCR for proper display.

 

A VCR, well... it does the same thing as a home VCR: it's a Video Cassette Recorder, and it records video.

[survtech 0]

Another difference between a quad and a multiplexer is that a quad always puts the four cameras into quadrants so each picture would be 352x240 or 320x240, but the recording would be at full fps (up to 25/30). A multiplexer normally sends each camera to the recorder in sequence so the resolution of each camera would be higher, up to 720x480 but the frame rate for each camera is typically 1fps or less.