In recent years, television coverage of the National Football League has become so rich and detailed that teams and stadiums have no choice but to respond with their own technology plays. Last spring the league’s commissioner, Roger Goodell, said the experience for fans in stadiums needed to be elevated to compete with television broadcasts, to keep fans engaged — and to keep them buying tickets — in a challenging economic climate.So why keep the TV broadcasts free? The broadcasts not only bring in a lot of money but they also eliminate barriers to fans encountering the NFL. Without that broad base, built on free content, you don’t have fans committed enough to spend money for tickets. There is something unique about the live experience. But the NFL is also realizing that it has to enhance the live experience (if not necessarily the games themselves) to compete with the free stuff they produce to draw people in the first place.To do that, stadium officials here have taken steps few other N.F.L. stadiums have. About $100 million has been spent on the stadium’s technology, and a former television production executive was hired to oversee the fan experience to offer more than fans can get sitting at home on their couches in front of their high-definition television sets…For those fans who do not have smart phones, 2,200 televisions with 48,000 square feet of screens have been installed in and around the stadium, the most of any N.F.L. stadium. The applications and stadium video screens will access video feeds that can be used only in the stadium because of the N.F.L.’s television agreements. If the fan leaves, the application will no longer work and will direct fans to the teams’ Web sites, which will offer less…The introduction of the smart-phone applications comes as teams confront an increasingly difficult environment to attract fans to stadiums. The images of N.F.L. players blocking and tackling on high-definition television have become increasingly life-like at the same time that the price of attending a game in person is higher than ever.