Multiple Sub-Nyquist Sampling Encoding
MUSE (Multiple sub-Nyquist Sampling Encoding), commercially known as Hi-Vision (a contraction of HIgh-definition teleVISION) was a Japanese analog high-definition television system, with design efforts going back to 1979. Traditional interlaced video shows either odd or even lines of video at any one time, but MUSE required four fields of video to complete a single video frame.
Source: Wikipedia — Multiple Sub-Nyquist Sampling Encoding (CC BY-SA 4.0)