It used dot-interlacing and digital video compression to deliver 1125 line, 60 field-per-second (1125i60) [2] signals to the home.
[6] MUSE employed 2-dimensional filtering, dot-interlacing, motion-vector compensation and line-sequential color encoding with time compression to "fold" or compress an original 30 MHz bandwidth Hi-Vision source signal into just 8.1 MHz.
[7] Japan began broadcasting wideband analogue HDTV signals in December 1988,[8] initially with an aspect ratio of 2:1.
Despite shadows and multipath issues in this analog transmission mode, Japan switched to a digital HDTV system based on ISDB.
[13] MUSE was developed by NHK Science & Technology Research Laboratories in the 1980s as a compression system for Hi-Vision HDTV signals.
[15] This makes it different from NTSC which carries luminance, audio and chrominance simultaneously in several carrier frequencies.
), a MUSE receiver can retrieve the original RGB color components using the following matrix:[3] The system used a colorimetry matrix specified by SMPTE 240M[5][27][28] (with coefficients corresponding to the SMPTE RP 145 primaries, also known as SMPTE-C, in use at the time the standard was created).
Originally, it was a 1125 line, interlaced, 60 Hz, system with a 5:3[15] (1.66:1) aspect ratio and an optimal viewing distance of roughly 3.3H.
The Japanese initially explored the idea of frequency modulation of a conventionally constructed composite signal.
The lack of visual response to low frequency noise allows significant reduction in transponder power if the higher video frequencies are emphasized prior to modulation at the transmitter and then de-emphasized at the receiver.
MUSE implements a similar system as a means of reducing bandwidth, but instead of static sampling, the actual ratio varies according to the amount of motion on the screen.
The DANCE system was well documented in numerous NHK technical papers and in a NHK-published book issued in the USA called Hi-Vision Technology.
The US television networks did not provide much coverage of MUSE until the late 1980s, as there were few public demonstrations of the system outside Japan.
Because Japan had its own domestic frequency allocation tables (that were more open to the deployment of MUSE) it became possible for this television system to be transmitted by Ku Band satellite technology by the end of the 1980s.
The US FCC in the late 1980s began to issue directives that would allow MUSE to be tested in the US, providing it could be fit into a 6 MHz System-M channel.
The Europeans (in the form of the European Broadcasting Union (EBU)) were impressed with MUSE, but could never adopt it because it is a 60 Hz TV system, not a 50 Hz system that is standard in Europe and the rest of the world (outside the Americas and Japan).
The EBU development and deployment of B-MAC, D-MAC and much later on HD-MAC were made possible by Hi-Vision's technical success.
Like Hi-Vision, HD-MAC could not be transmitted in 8 MHz channels without substantial modification – and a severe loss of quality and frame rate.
A 6 MHz version Hi-Vision was experimented with in the US,[8] but it too had severe quality problems so the FCC never fully sanctioned its use as a domestic terrestrial television transmission standard.
The US ATSC working group that had led to the creation of NTSC in the 1950s was reactivated in the early 1990s because of Hi-Vision's success.
Many aspects of the DVB standard are based on work done by the ATSC working group, however most of the impact is in support for 60 Hz (as well as 24 Hz for film transmission) and uniform sampling rates and interoperable screen sizes.
[12] There were a number of MUSE LaserDisc players available in Japan: Pioneer HLD-XØ, HLD-X9, HLD-1000, HLD-V500, HLD-V700; Sony HIL-1000, HIL-C1 and HIL-C2EX; the last two of which have OEM versions made by Panasonic, LX-HD10 and LX-HD20.
These machines, unlike conventional type C VTRs, are incapable of showing images while paused or playing the tape at low speeds.
However they may be equipped with a frame store to capture images and display them while fast forwarding or rewinding the tape.
Two tracks for green chrominance plus luminance are used to increase the bandwidth of these signals that can be recorded on the tape.
The VTR uses Iron metal oxide tape with cobalt for high coercivity, with capacity for 40 MHz of bandwidth at a head drum speed of 3600 RPM, which is sufficient for applying FM modulation to 10 MHz signals.
[48][49][50][15][45][25] In 1987, technical standards for digital recording of Hi-Vision signals were released by NHK, and Sony developed the HDD-1000 VTR as part of their HDVS line, and Hitachi developed the HV-1200 digital reel to reel VTR.
Video is recorded in groups of 4 tracks or channels, which are side by side length-wise within each helical track, to allow for parallelization: high total data rates with relatively low data rates per head, and reduce the linear tape speed.
Reed-Solomon code is used for ECC and each line also has an ID number for trick play such as slow motion and picture search/shuttle.
[15] This videocassette format was developed in order to reduce the size of HD recording equipment.