View source for EIAJ MTS

{{Confusing|date=June 2020}}
'''EIAJ MTS''' is a [[Multichannel Television Sound|multichannel]] television sound standard created by the [[EIAJ]].

[[Multilingualism|Bilingual]] and [[Stereophonic sound|stereo sound]] television programs started being broadcast in Japan in October 1978 using an "[[Frequency modulation|FM-FM]]" system originally developed by the [[NHK Science & Technology Research Laboratories|NHK Technical Research Labs]] during 1962–1969. This system was modified and standardised by the EIAJ in January 1979. Television stations in Japan with capability for bilingual and stereo sound transmissions used the callsign JO**-TAM, where "TAM" denotes their audio FM [[Sound multiplex in broadcasting|multiplex]] sub-carrier designation, until digital switchover to [[ISDB-T]] in 2010–2012 which eventually rendered EIAJ MTS obsolete.

The original [[CCIR System M|System M]] TV standard has a [[monaural]] FM transmission at 4.5&nbsp;MHz. For Japanese multichannel television sound a second channel, or sub-channel, is added to the original signal by using an FM sub-carrier at twice the line frequency (Fh, or 15374&nbsp;Hz). In order to identify the different modes (''mono'', ''stereo'', or ''dual sound'') a [[pilot tone]] is also added on an AM carrier at 3.5 times the line frequency. The pilot tone frequencies are 982.5&nbsp;Hz for stereo and 922.5&nbsp;Hz for dual sound. Contrary to [[Zweikanalton]] these pilot tones are not coupled to the line frequency but were instead chosen to allow use of filters already employed in the Pocket Bell [[pager]] system.<ref>{{cite journal|last=Numaguchi|first=Yasutaka|title=Present Status of Multichannel-Sound Television Broadcasting in Japan|journal=IEEE Transactions on Broadcasting|date=December 1979|volume=BC-25|issue=4|pages=128–136|doi=10.1109/TBC.1979.266340|s2cid=19830970}}</ref>

== See also ==
*[[Multichannel Television Sound]] (3 additional audio channels on 4.5&nbsp;MHz audio carriers)
*[[NICAM]]
*[[Zweikanalton]] A2

== References ==
{{Reflist}}

{{Video formats}}

[[Category: Broadcast engineering]]
[[Category:Television technology]]
[[Category: Sound]]


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