Breaking Down The NFL Instant Replay System

During the past 10 years the National Football League's instant replay system has changed a lot. From upgrades to its overall rules, to the equipment that the officials use, it has been hard for a fan to keep track of all the changes from season-to-season. So, with the start of the 2009 season nearly upon us, we want to give you an inside look at what really happens from a technical side of an official replay. (For a more precise look at the upgraded "Rules" that regulate instant replay, check out the NFL's official website.)

The Equipment:

On-Field Monitors: In each of the NFL stadiums around the country there are two Panasonic 26-inch LCD BT-LH2600W monitors located on the field. These two monitors are set up on opposite sidelines for quick access for the referee to use. Although the monitors are the same in both stations, the image quality is very different. On the home sideline is one monitor that receives a high definition signal, while on the visitor's sideline the monitor receives a standard definition signal. The referee uses the standard definition monitor only if there are technical difficulties with the HD monitor. (This is one of the newest additions to the NFL's instant replay system.) Prior to the 2007 season no HD signals were set up for use with the instant replay system. But that changed once the NFL felt pressure to upgrade so that the officials were getting the same quality of image that fans were getting on their home TVs. Along with the clearer-image quality that the HD signal gave, referees were also given the opportunity to freeze the action on the replay for a more precise call on the field.

Official's Booth: Even with a much larger space up in the booth, the enclosed review station has the same Panasonic 26-inch LCD BT-LH2600W monitors as the on-field stations. According to Jeffrey A. Howard, senior executive engineering & broadcast technologies for the NFL, the monitors don't need to be bigger since the officials stand so close to their displays. And just like the on-field HD monitor, the replay booth's HD displays are set up with the same freeze-action control for precise looks.

Production Truck: The host network broadcast trucks are located at the stadiums and serve as the preliminary stage for the replay signal. Here the action on the field is recorded and fed out to the Replay System Fiber Distribution System (a system of cables), which then sends the signal up to the replay booth. Harris Nexio Servers: Located in the replay booth overlooking the field are two Harris Nexio servers. These simultaneously record the signal from the fiber distribution system, which then send the signal to the monitors on the field. Step-By-Step Guide:

Now that you are familiar with the equipment used to transmit, carry and watch the replay, here's a look at how the signal gets broadcasted throughout the stadium. 1. The host network broadcast production truck hands an HD signal off to the Replay System Fiber Distribution System in the truck bay of the stadium. 2. Fiber carries the network program feed to the replay booth where it is recorded on two Harris Nexio broadcast servers simultaneously. 3. HD replay video is fed from the booth down to the HD field review station via the Replay System Fiber Distribution System. SD replay video (as a back-up) is fed over broadcast copper coaxial cable to the back-up SD field review station.