How is the digital television signal in the U.S. primarily modulated for over-the-air broadcasts?

The digital television signal in the U.S. is primarily modulated using 8-VSB (8-Level Vestigial Sideband) technology. This modulation technique is specifically designed to optimize the transmission of digital signals over the air, allowing the broadcast of high-definition television and standard-definition television.

8-VSB is particularly efficient in terms of capturing and processing the digital signal, making it more robust against interference and able to maintain quality over various reception conditions. The choice of 8-VSB for over-the-air broadcasting in the U.S. was established as part of the transition from analog to digital broadcasting. This transition was a key moment that allowed for the more efficient use of the electromagnetic spectrum and improved picture and sound quality for viewers.

Other methods mentioned, such as COFDM technology, are widely used in different regions of the world, specifically in Europe for digital television broadcasting. MPEG-2 compression is not a modulation technique but rather a method for compressing video and audio signals, which is essential for efficient transmission, but it does not pertain to how the signal is modulated for broadcast. Analog modulation refers to the older technology used before the digital transition and is not applicable to current digital broadcasting standards in the U.S.