From what I've read, Zenith at one time had quite a R&D lab and were well known for new and novel developments. This included both tube technology and even HDTV. Some say that their HD system should've been selected as it's compatible with existing analog broadcasts.

This reminds me of the NTSC/RCA standard versus the rejected CBS system. The FCC made the right decision back then but blew it this time around.

Anthony