Simple IMAG System

The above Image is a Flow Chart of a very simple IMAG video system, it is in no way shape or form an Engineering Schematic (or one line).  The purpose of the Flow Chart is to show you the gear and signal flow involved in a video system.  Please work with an integrator to design the system that you need.  This flow chart is Video only and doesn’t show Control, audio or Com.  If you are considering installing a video system, also see:

1)   Production Switcher:  The production switcher is the heart and soul of your production, It allows you to mix between sources and set up layering through keying.  Although in may not be the most important piece in you control room, it is what provides you the most flexibility and options in your production.  Usually the production switcher has two pieces, a panel (1a) and a frame (1).

2)   Router:  This is the Hub of you facility.  Everything should route in and out of your Router for optimum flexibility.  Lines should go from your production switcher to your router & visa-versa.  However, it isn’t recommended that your router feed all the sources of your Production switcher, it is recommended to run dedicated lines to both devices for primary sources such as Cameras, and Character Generators. Routers also commonly come in multiple pieces such as panel and frame.

3)   Sync/ Pulse/ Test signal Generator: A small device but probably the most important piece in the system is the Sync Generator. It provides all sources a reference signal to setup proper timing.  A properly timed system with have smooth transitions and low latency.  Every device in your system should receive a Reference signal, especially if it is outputting signal into the system. Also see:

4)   Studio Cameras:  Studio cameras are what capture your talent for IMAG.  This is the most important part of you system because this dictates the quality of your production,  lower quality cameras mean lower quality content. Studio cameras are recommended because they give your operators the tools they need to succeed such as return video (the ability to see sources from the control room, usually Program), Tally (an on air light on the camera to indicate when the camera is live), and Com for communication from the control room. Also see:

5)   CCU(Camera Control Unit):  The camera control unit is the input/output for the camera.  It takes all incoming and outgoing signals from the system and mux’s them down 1 line such as SMTE hybrid Fiber, Triax or Multi-core.  It will also have a way of accessing all the camera functions such as white balance and iris from the control room either on the CCU itself of via a remote control unit (AKA: OCP, RCP, or Paint box)

6)   Frame Sync:  Everything in your system needs to receive a reference signal to offer correct timing.  A frame sync takes untimed signals and times them to the system.  Depending on which one you purchase most external Frame syncs can also act as signal converters from composite or Component to SDI, or a just re-time an SDI signal.  These are great for POV cameras, DVD players and anything else that is consumer or Pro-sumer.

7)   CG (Character Generator): A CG provides text and graphical elements such as lyrics to your show.  A proper CG should offer both a Fill and Alpha (key) signal for perfect keying over video. (For a better definition of Fill and Key see the Broadcast Terms page)

8)   Video Playback Deck:  Playback has changed forms in the last 5-10 years.  It used to be a tape deck, but more recently has switched to the form of Video servers and Digital decks.  Most IMAG systems use computers using a software form of playback, either way I recommend a dedicated machine (or two) for playing videos.

9)   Scan Converters:  A scan converter takes a computer display signal such as VGA or DVI and converts it to SDI and times it into the system.

10) Wave form/ Vector Scope:  This is what is used to calibrate your cameras and devices into your system to make sure the signal is clean and colors match.  Mostly used by a Shader to control iris’s during a show.  Scopes are expensive but extremely valuable and often under rated.  Be sure to leave budget in your system for a proper scope.

11) Projectors:  This is what your audience see’s, without proper projection your IMAG system is useless.  Be sure you get a projector with low latency, proper lumens, and good processing.  Also see

12) Record Decks:  It is always a good idea to record your show.  Be sure to choose a deck that can do it at the quality your are shooting and gives you a usable format on the output.  Also make sure the media you are recording to can handle long periods of recording time.  Choose your record deck carefully as not all of them are the same and some of them may require extra external devices to make them work the way you want them.

13) Modulator:  Modulators are used to convert your system to an RF based signal such as CATV.  The great thing about RF is the ability to  handle a large amount of TV’s at a low cost.  If you have a few TV’s you may want to use a Distribution amp and converters instead of a modulator.  In my design I have a analog modulator because cost effective Digital ones have a large amount of delay  and don’t work well in a building doing live production.  Also know that balancing an RF system can be very difficult and can take lots of time.

14) Multi-viewer:  You need to see all or most of your inputs and outputs.  Monitoring is the key to a successful production.  In my basic design I chose a production switcher that has a multi-viewer built in, but know that not all switchers have them built in and would require another form of monitoring.

15) Distribution Amplifier (DA): A DA multiplies the signal.  Do not use T or Y adapters with video.  DA’s come specific for many different kinds of signal types, Analog, SD-SDI, HD-SDI and 3G-SDI, in Equalizing and Re-clocking, be sure to get the proper DA for what you need.  I also recommend looking at a frame based DA’s such as the Open Gear Frames/ cards.

16) Down converters:  Any time you need change from an SDI level signal you need a converter.  You can get a converter to go from SDI to pretty much anything.  Go through your gear and make sure you have all the signal converters you need before purchasing.  Also look at Up/Down/Crosses to go from SD-HD and HD-SD and HD720-HD1080, UDC’s can also usually Change aspect ratio’s and in some cases add Wings to 4:3 images.

Also see these pages:


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