LaserDisc Database :: View topic - Tapping composite video from LD-S2

I'm interested in seeing what the composite video looks like on my LD-S2 before it goes through the TBC. Looking at the service manual, there's a tap point for the video right before the TBC IC, and this is actually what the manual tells you to monitor when setting video level.

I would be feeding this signal into a broadcast grade infinite window TBC. The question I have is about the video level and the non-standard sync some have mentioned. The video level before the TBC is 0.8V p-p instead of the standard 1.0V p-p and I'm not sure what the sync is like. Is the video signal at that point even usable?

Author:	gumbyandpals [ 30 Nov 2013, 16:36 ]
Post subject:	Tapping composite video from LD-S2
I'm interested in seeing what the composite video looks like on my LD-S2 before it goes through the TBC. Looking at the service manual, there's a tap point for the video right before the TBC IC, and this is actually what the manual tells you to monitor when setting video level. I would be feeding this signal into a broadcast grade infinite window TBC. The question I have is about the video level and the non-standard sync some have mentioned. The video level before the TBC is 0.8V p-p instead of the standard 1.0V p-p and I'm not sure what the sync is like. Is the video signal at that point even usable?

Author:	grasshopper [ 30 Nov 2013, 16:48 ]
Post subject:	Re: Tapping composite video from LD-S2
gumbyandpals wrote: I'm interested in seeing what the composite video looks like on my LD-S2 before it goes through the TBC. Looking at the service manual, there's a tap point for the video right before the TBC IC, and this is actually what the manual tells you to monitor when setting video level. I would be feeding this signal into a broadcast grade infinite window TBC. The question I have is about the video level and the non-standard sync some have mentioned. The video level before the TBC is 0.8V p-p instead of the standard 1.0V p-p and I'm not sure what the sync is like. Is the video signal at that point even usable? Yea, TBC is Jitter control to keep a stable looking picture, example tape cassette has wow and flutter except the bwey good decks. Ao basically the ld picture is going to show wow and flutter mayne not bad though.

Author:	happycube [ 01 Dec 2013, 02:22 ]
Post subject:	Re: Tapping composite video from LD-S2
Here's an example of what a pre-TBC composite signal looks like: https://raw.github.com/happycube/ld-dec ... bar.ld.jpg

Author:	gumbyandpals [ 01 Dec 2013, 03:12 ]
Post subject:	Re: Tapping composite video from LD-S2
Thanks for the pic happycube. I guess my ultimate goal would be to feed the pre-tbc composite into an outboard TBC to compare that video to the standard composite out of the LD-S2. I want to see how the video processing in the player affects the signal. A lot of people assume that using more modern signal processing could yield better results but I guess we don't know that until we compare. Choosing/designing a buffer circuit for the video output is where I fall short. I just don't know enough about NTSC video and related circuit design.

Author:	elahrairrah [ 02 Dec 2013, 22:03 ]
Post subject:	Re: Tapping composite video from LD-S2
Publius mentioned in this thread how someone was tapping the digital composite signal from the TBC in an LD player. This was after TBC rather than before like you are asking, so I'm not sure if that helps. He does provide a link to the thread from another forum where the user is trying to do this. Maybe that will help you if he explains how he does this?

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