Cable Reference Guide - Audio Intervisual Design, Inc.

LYNX TIME CODE MODULEAppendixIn video and digital audio applications, always make sure that thetime code generator and machines are properly referencedtogether when printing time code. Your generator must beconnected to the same external video sync signal as the video ordigital machine, otherwise, when synchronizing, the videomachine’s will start off in the right place, then slowly drift apart.With digital audio machines, the sample rate or word clock mustbe locked to the time code. This is normally done by using a videosync signal as a common timing reference for the generator andthe digital machine. Set both to “EXT VID” before printing timecode. If you do not have a sync pulse generator, the Micro LynxVideo Sync Generator (VSG) option card can be installed and usedto generate a referenced composite sync signal for your video ordigital machine.Specific types of video sync include black burst, color bars andcomposite. These video sync signals are often collectively calledhouse sync, or the signal that’s universal throughout theproduction facility or house. To reference your generator to videosync, set it to “EXT VID” mode and connect a video sync signal.This ensures that the tapes you are striping will have a commonreference and on playback will sync properly.Reshaping Time CodeReshaping, or cleaning up the time code signal, should always beperformed when dubbing time code from one tape to another. Ifyou simply copy time code from one tape to another without reshaping,it will deteriorate quickly due to generation loss and willeventually become unusable. Reshaping is not recommendedwhen the time code on tape has begun to deteriorate badly.TIME CODE INLYNX MODULERESHAPED TIME CODESMPTE007AFigure Appendix A-8. Reshaping Time CodeWhen reshaping, existing code is passed through the reader,which puts out “squared-up” code. If a tape has been copiedseveral times or is very worn, then it is likely that the time codewill have dropouts or bad spots that a time code reader will not beable to read. The reshape output of a time code reader can onlyput out a clean copy of its input. So if the code drops outcompletely, the reshaped output will have a correspondingdropout. To overcome this, the code must be regenerated ratherthan reshaped.Micro Lynx06/22/00 A-15