Composite Video Blank and Sync (CVBS)

Okay lets start with probably the most important part of broadcasting transmission, which is the signal. there are a number of video signals, but we are going to look at the main ones at which are used in this country frequently. each singal will have different names but all have been set to the same standards. These names will need to be known as to better help in the industry when talking to other engineers. When i say standards i mean the parameters of a signal that have been met and produced by a group of engineers which then gets put into the systems to help the distrobution of from one machine to another even when made by different manufacturers. Well it can be argued as there is a lot out there we tend to use the signals provided by top manufacturers such as Sony, Grass Valley, EVS and so on.

Composite Video Blank and Sync (CVBS)

The composite signal is a single signal which carries all of the active video information, red green and blue, along with the luminace blanking and sync. When viewing this signal through a waveform monitor we can see that the ideal amplitude is between one volt peak to peak.

Fig. 1

In Fig. 1 it shows the amplitude being 1.2 volts peak to peak. even though the ampiltude is 200 mV above ideal value this is still a safe enough to push through a monitor. the waveform monitor will warn if the amplitude is too high by highlighting red. An amplifier can be used here providing that it has the ability to adjust the gain manually to bring it to a correct level.
Composite has the ability to distrobute PAL and NTSC signal standards just to name a couple. PAL being what we use in England at a rate of 25 frames per second with horizontal lines in total or 576 active lines. Fig 1 is colour bars set to 100% and is used to accuratly test equipment. It just makes it easier for us when we go E-E that the signal coming out of the equipment is as going in or correctly adjusting monitor brightness, contrast and colour. Most equipment now will have a colour bar generator built in to correctly set up external equipment.