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RE: OT: Processing video signals as audio?

Title: RE: OT: Processing video signals as audio?

>>The bottom line is that here's no way anyone is going to record or process video on audio gear. nice idea though...<<

been running around all morning doing video engineering or I might've chipped in a little earlier.....

to cut a very long story very short, in order to construct a high resolution picture, the video signal (& let's ignore for the moment the differences in line structure & colour encoding method between PAL & NTSC) has to accommodate the entire range of frequencies between field/frame rate (& actually this is d.c. to all intents & purposes, since the waveform is assymmetrical- video in the top half & synchronisation pulses in the bottom half) & the highest frequency picture information, which is up around 5-6MHz.

that's something like 15 octaves or more.
if you know anything about how tape recording works, you'll know that for every doubling of frequency, the level-off-tape also doubles. (rate of change of flux density with time....).

this presented the early vtr engineers (including a very young ray dolby) with a problem- how to record that much spectrum & still manage a respectable signal/noise ratio. the answer was to use r.f. techniques to compress the frequency range, the same method used in radio transmission. ampex switched from a.m. to f.m. fairly early on & vtr's stayed with this method until relatively recently........


this is a great site with a good account of the first vtr; elsewhere there is more reading on tv technology for those sufficiently interested. everyone else- sorry this wasn't about looping.



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