hrome sets. In Germany, the Telefunken found that the NTSC standard caused phase errors introduced during signal propagation that, in turn, resulted in uneven color reproduction. To cancel out the phase errors, the Germans inverted the color signal by 180 degrees on alternate lines. More than 40 countries including the U.K., Germany, and Western Europe (except France) adopted phase alternate line (PAL). The French adopted an FM system to transmit color television information that eliminated the phase error problem. The French system SECAM (Sequential Couleur Avec Memoire), separates color information into red and blue and sends it by two alternating carriers. A memory circuit within the TV set remembers the signals and uses them for faithful color reproduction. The NTSC system has seen few changes since 1953. Modulating the already compromised signal onto an RF subcarrier amplifies the system's inherent problems. Once propagated in free space, it is fair game for interference from a wide variety of random signals-a phenomenon known as radio frequency interference or RFI. Cable television eliminates most RFI problems, which may explain why the system has lasted SO long. In spite of its glitches, color TV still relies upon the NTSC system because the U.S. was slow to approve a digital television standard, which is gradually replacing the NTSC system. Video Communications: The Whole Picture By the year 2010, the FCC may ban analog TV transmitters from the airwaves if the 98% of Americans (who own most of the world's 600+ million television sets) either upgrade to HTDV or buy digital adapters for existing sets. HDTV sets display engaging wide-screen, high-definition images with about twice as many scanning lines as NTSC. HDTV also offers simultaneous broadcast of multiple channels of sound. HDTV offers unprecedented image, sound, and interactivity. HDTV is a logical successor to NTSC in part because it offers the sense of involvement that audiences appreciate in the wider screens that theaters offer. HDTV offers grea