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Started by soetensboy, March 15, 2005, 14:18:01
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QuoteTIME BASE CORRECTOR (TBC) AND/OR SYNCHRONIZER (SYNC)Courtesy of: PRIME IMAGE, INC.By: William B. Hendershot III, PresidentWhy Do I need a Time Base Corrector (TBC) ?If you don't have a video tape recorder (VTR or VCR) you don't need a time base corrector (TBC). However, you may need a synchronizer, which is commonly confused with a TBC. Definitions and applications of both are explained in this paper.If you have a VCR you need a TBC. Consumer VCRs may be excluded - unless used for edit or dub/ then a TBC is needed.Without VCRs, which generate time base errors in television pictures, there would be no need for time base correctors. Put in other terms, if VCRs and video tapes were mechanically perfect, there would be no time base errors to correct -- but like the world and all that is in it, perfect does not exist. TBCs are needed to electronically make television pictures played back from imperfect VCRs and tapes as near perfect (stable) as possible.What Is Time Base Error?It is mechanical error or change. In the case of video tape, the errors are introduced by temperature, humidity, drag and tension changes which alter the physical size or shape of the tape at the time of playback versus these same parameters at the time of recording. In the case of the VCR these are errors introduced by mechanical size, shape and condition of the tape path, which changes the physical size and shape of the tape at the time of playback versus these same parameters at the time of recording.Changes in size or shape of video tape smaller than one thousandth (1/1000 of an inch on a day-by-day VCR to VCR basis is nearly impossible -- electronic control of these mechanical errors in a TBC is nearly perfect.What Does Time Base Error Look Like?It manifests itself as geometric distortion in the television picture playback. The most common type of time base error shows up as a bent or curved line in what should be a straight vertical line in the picture monitor (visualize a flag pole with bends in it -- the TBC makes the pole straight again). Sometimes the time base error changes as the tape is played back, causing the bends or curves to change shape or wave back and forth. The top of a picture played back from a VCR is almost always displaced to the right or to the left due to time base error. The TBC removes this displacement.Do You Need A TBC?Is Your VCR Perfect?1. TBCs make clean edits possible by locking the VCRs to the same external sync generator.2. A sync generator and a synchronizer (SYNC) are two different pieces of electronic equipment.3. All high quality TBCs have built-in sync generators which reinsert clean H-sync, V-sync and burst on the video signal. For example all Prime Image TBCs have built-in sync generators with clean H-sync, V-sync and burst at both output ports. This is just a side benefit from a TBC that is needed anyway.The Super TBCIn the beginning there was a time base corrector (TBC) and then a synchronizer (SYNC).First There Were Time Base Correctors (TBC)These TBCs made electronic news gathering (ENG) possible by removing small rapid time base errors from smaller, less expensive VCRs. In 1973 Consolidated Video Systems (CVS) introduced the world's first digital TBC which stabilized errors from these smaller, less expensive VCRs, so they would meet FCC broadcast requirements and ENG was born. CVS received the Emmy for this pioneering work. These early digital TBCs were 10 1/2" D and 19" rack mountable; they sold for about $10,000 (over $20,000 in today's dollars). Then Came The Synchronizer (SYNC)These SYNC units locked remote feeds to local station sync making possible clean switches, fades, splits, etc. between local and remote non-synchronous picture sources. This was accomplished by removing large slow time base errors from microwave, cable and satellite feeds.At the 1974 NAB Show both CVS and NEC introduced the world's first digital synchronizer (SYNC). These early SYNCs were 7' H, 30"D in 19" racks, running off of 220 volts and selling for about $80,000 (over $150,000 in today's dollars).And Now The Super TBC (TBC/FREEZE-II)At first the TBC and SYNC were clearly two different products. Now they can be combined to form a Super TBC which removes rapid time base errors from VCRs and at the same time provides V-lock by removing slow time base errors from non-capstan servoed VCRs.Example:The (TBC/FREEZE-II (50-II) from Prime Image, Inc. is a Super TBC providing both full frame synchronization and time base correction in a 1 3/4" H, 16" D, 19" rack mount unit for under $2,000. The 50-II also provides frame and field 1 or 2 freeze, and frame and field strobe effects while consuming less than 20 Watts at 110V.These Super Full Frame TBCs (50-II) make possible true A/B roll edits between non-capstan servoed (non-V-locked) VTRs. The resultant output is true interlaced phased color even when the VCR playback is only heterodyne color. From TBC to SYNC To Super TBC (50-II)less powersmaller sizelower costmore featuresDigital Effects In A TBC or SYNCSince TBC and SYNC equipment convert the TV picture to the digital domain to accomplish their basic function, it requires few additional parts and therefore very little additional cost to provide digital effects within these same units. TBC and SYNC units are needed to meet FCC Broadcast requirements and digital effects are desired in many cases. Some manufacturers provide TBC and SYNC units either with or without digital effects -- they choice is yours.All TBC Digital Effects are possible in a full frame SYNC plus various full picture freeze and strobe effects. Full proc amp should always be included.1. Freeze frame: entire full 525 line TV picture is frozen in a full frame digital memory. A frozen frame yields the best possible vertical resolution. Note: A TV frame consists of two TV fields (262 1/2 lines).2. Freeze field: in quality SYNC units field #1 or #2 can be frozen. Usually in these units the full frame is frozen and field #1 or #2 can be selected to display as a frozen picture.Note: A frozen field has only half the vertical resolution of a frozen frame; however, a frozen field can be used to remove flicker from a frozen frame created when a picture with moving objects is frozen. Therefore, A SYNC with both frame and field #1 or #2 freeze yields the best of all worlds.3. Strobe: a strobe effect is created by repeatedly freezing the incoming TV picture. The strobe or freeze rate should be variable from real time to a fixed frozen picture. Both strobe frame and field should be available to create the most desired variation of strobe effects. Other Considerations:1. Multi Channel: The Multi-II provides from 1-to-10 Channels of TBC and SYNC in one 3U high rack mount unit with full monitoring capability and front panel control of up to 32 parameters per channel. Also controllable through a 232 port or Model #R-1 remote.2. Component/ Transcoding: The C-SYNC is a full frame SYNC/TBC with Component (YRB), Y/C and Composite in/out and full transcoding between all inputs/outputs. Up to 32 parameters can be controlled from the front panel of this 1U high rack mount unit for under $3,000. Also controllable through a 232 port or Model #R-1 remote.3. 2-Channel, A/B Roll Editing: The Model "TWO" is a dual channel full frame SYNC/TBC specially designed for A/B roll editing. The "TWO" is in a 1U high rack mount frame with full controls on the front panel, controllable through a 232 port or Model #R-1 remote.4. TBC/SYNC on a PC Board: The "Xpon" is a transcoding component (I/O) full frame SYNC/TBC on a 12 oz. board that will plug into any computer with an AT-Bus. The "Xpon" exceeds all broadcast specifications with true component (YUV) capability. Over 32 parameters on the "Xpon" can be controlled through the computer or through a hand held remote.
Quote from: soetensboy on March 15, 2005, 16:45:09Wat ik nog niet helemaal uit je verhaal opmaak is het volgende: kunnen de eisen en wensen die ik heb met die Onkyo 602 reveiver nou wel of niet?Alvast bedankt
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