generate questions: There were four major HDTV systems tested by SMPTE in the late 1970s, and in 1979 an SMPTE study group released A Study of High Definition Television Systems:
How many major HDTV systems were tested by SMPTE in the late 70's? {sep_token} Who tested the four major HDTV systems in the late 1970's? {sep_token} Who released A Study of High Definition Television Systems? {sep_token} In what year was A Study of High Definition Television Systems released? {sep_token} What was released by an SMPTE study group in 1979? {sep_token}