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TBC and jittery signals from decks This transcoder requires a clean signal. The jittery signal from playback on a VCR is not good enough. You must pass the signal through a TBC first. Of course you could also use the TBC to do the transcoding, but thats a seperate issue.
Signal Delay The DEC-6801 seems to delay the input signal by 1/8 of a frame width. While this is a short amount of time, its annoying if your signal started out genlocked, and comes out still synced, but delayed a little. If this signal later passes through the Faroudja for example, it will get shifted over since the sync line into the Faroudja is not delayed. There is an add on card, that turns this thing into a DES-6801, which adds a frame sync fixing the problem. We didn't get it, and I think its reasonanbly expensive. Another option would just be a delay circuit that would force a full scan line of delay which isn't as bad as 1/8 scan line, since you won't notice a downward shift of one. These things are about $200, but I think there are signal quality issues. Delay lines I think suppress high frequencies.
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Last modified: Wed Nov 11 01:25:00 PST 1998