* أجهزة البث والاستقبال التلفزيوني** سيكام** تردد فوق العالي** IRE وحدة* U.S. cable television channel frequencies* TVTower.com - Commercial Television Frequencies* Representation of the NTSC refresh rate on a television and on a DVD
==External links==*National Television System Committee* U.S. cable television channel frequencies* TVTower.com - Commercial Television Frequencies* Representation of the NTSC refresh rate on a television and on a DVD* Why 59.94 vs 60 Hz