VoyForums
[ Show ]
Support VoyForums
[ Shrink ]
VoyForums Announcement: Programming and providing support for this service has been a labor of love since 1997. We are one of the few services online who values our users' privacy, and have never sold your information. We have even fought hard to defend your privacy in legal cases; however, we've done it with almost no financial support -- paying out of pocket to continue providing the service. Due to the issues imposed on us by advertisers, we also stopped hosting most ads on the forums many years ago. We hope you appreciate our efforts.

Show your support by donating any amount. (Note: We are still technically a for-profit company, so your contribution is not tax-deductible.) PayPal Acct: Feedback:

Donate to VoyForums (PayPal):

[ Login ] [ Contact Forum Admin ] [ Main index ] [ Post a new message ] [ Search | Check update time | Archives: 1, 2, 3, 4, 5, 6, 7, 8, [9], 10 ]

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Date Posted: 08:52:23 02/12/02 Tue
Author: Potter
Subject: Re: Black border
In reply to: Jain 's message, "Re: Black border" on 08:22:42 02/12/02 Tue

The code regenerates the sync so if the timing's a little out the TV accepts it even if it's not in the right place in relation to the video - try changing the delays in makehline to shift the sync in right direction without changing the total cycles spent in the routine (this may affect locking so the lockon routine might need tweaking as well to return to makehline with the real sync edge in the right place). The time spent passing the video may need to be balanced with the above (ie extended) to prevent starting the front porch too soon and blanking the end of the lines. I had to set my code up by viewing the input and output on a dual trace cro to get the regenerated Hsyncs in the exactly the right place considering that the propagation delays of the edge detectors (LM339 comparator) vary.

>Funny is that on unscrambled channels there are more
>lines 'missing'.
>I guess is the code the culprit.
>On a normal tv set you don't see the black border
>(usualy, vertical and horrizontal dimensions are biger
>than the screen; but I was workind (during tests) with
>a tv addapter for PC, and there you can see clearly
>the black border.
>J
>
>>Might be the code, not matching the local system or
>>improper lock of the PIC...
>>
>>Mike
>>

[ Next Thread | Previous Thread | Next Message | Previous Message ]
[ Contact Forum Admin ]

Forum timezone: GMT-8
VF Version: 3.00b, ConfDB:
Before posting please read our privacy policy.
VoyForums(tm) is a Free Service from Voyager Info-Systems.
Copyright © 1998-2019 Voyager Info-Systems. All Rights Reserved.