[QuadList] Two Inch Quad Stereo Recording--NBC Burbank--PCM Audio at NBC-NY

[Dennis Degan]

		On Aug 21, 2014, at 7:46 PM, Ted Langdell wrote:

> The April/May 1976 issue of RCA Engineer has a comprehensive package of articles on NBC NY's facilities for switching, transmission and machine control:
> http://www.americanradiohistory.com/Archive-RCA-Engineer/1976-04-05.pdf
> On Page 42, there's an article about how Pulse Code Modulation was used to put four audio channels into the video for routing within the NY facilities. What happens at VTRs is described.  There were 44 VTRs and cart machines in NY at the time.

		I say:

	I worked with this system when I started at NBC in 1978.  Though the 'Master Grid' could handle 4 channels of PCM audio (at 12 bits), it was only configured to transport 3 channels of audio.  I was there before the technical plant was converted to stereo operation.  None of the VTR's were equipped for stereo at that time.
	The router was prone to 'crackling' audio, which was essentially caused by dropped data, lost in noise.  The error correction was not very robust.  NBC maintained the most critical cross points for BOC, although of course ALL crosspoints could be considered critically important at various times.  Crackling audio was heard on the air throughout the period in which this router was used in the 30 Rock plant.
	I don't recall ever seeing a manufacturer's name on any part of the router.  It may have been built in-house.  I don't think it was made by NEC as the equipment does not match any known NEC racks of that period I've seen.
	Here is a 1976 shot of part of the router, located in the central equipment room at NBC-NY:
		https://www.flickr.com/photos/dennisdegan/515347674/

			Dennis Degan, Video Editor-Consultant-Knowledge Bank
					    NBC Today Show, New York


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