[QuadList] Heterodyne

[Kenneth Zin]

Early VTR did not have Time Base Correctors, to playback color they use heterodyne.  The playback signal with jitter has the horiz sync separated and multiply up to either 3.58MHz or 7.16MHz this is "sync 
coherent" 3.58MHz and that is used for the heterodyne process, thus the jitter of the demod signal is the same as the color. 
These heteroydyne systems were used on the early vtr's before time base corrector.  Heterodyne bandwidth is limited to the 3.58MHz or 4.43 MHz. If you record the heterodyne signal, now you have a problem,
you have the playback machine with its time base errors and the record
in time base errors of the other machine which made the heterodyne color. That what we have when viewing the Nixon Kruschev kitchen debate tape, as the original tape were use for the conversion.
Ken Zin