i have changed the subject as it did not relate to my initial thread and got bored of reading things that i was not interested in 2017-02-20 10:00 GMT+01:00 <groepaz@gmx.net>: > On Monday 20 February 2017, 09:55:11 HÁRSFALVI Levente > <publicmailbox@harsfalvi.net> wrote: > > On 2017-02-20 08:26, groepaz@gmx.net wrote: > > > On Monday 20 February 2017, 08:19:57 Gerrit Heitsch > > > > > > <gerrit@laosinh.s.bawue.de> wrote: > > >> On 02/19/2017 11:47 PM, HÁRSFALVI Levente wrote: > > >>> Another addendum: Marko once measured the luma levels of different > > >>> VIC-II chips in the same C64 motherboard, > > >>> http://www.zimmers.net/anonftp/pub/cbm/documents/ > chipdata/656x-luminance > > >>> s. > > >>> txt> > > >>> > > >>> . I don't know how well the data practically holds, since the > > >>> > > >>> measurements have been done without using a standard 75 ohm load; > yet, > > >>> one thing seems to be sure: there are slight differences between > > >>> different VIC-II chip revisions in the luma levels they produce. > Maybe > > >>> part of what I've seen has been a result of that. I can't speak of > the > > >>> other symptoms, I didn't make measurements myself. > > >> > > >> We have to remember that VIC is a bit of a mixed signal chip, it is > > >> mostly digital, but also produces analog signals. I take it as a given > > >> that there will be slight differences between VICs of the same > revision, > > >> even if they come from the same wafer, let alone from different > > >> production runs where the process was tweaked over time. > > >> > > >> So measuring luma levels only counts if you have multiple VICs of each > > >> revision you can compare against each other. > > > > > > indeed, some other ppl checked the luma levels in the past decades, and > > > its > > > always slightly different :) > > > > The question here would be IMHO whether there is a correlation between > > VIC-II revision numbers and the luma maps the respective chips produce. > > The rest (general phenomenon of output level variances of mixed signal > > chips, general statements about measurement variances due to people > > measuring video signals with different / generally inadequate equipment > > etc. etc. etc.) is obvious. > > unfortunately, to find that out... you'd have to check quite a few chips. i > dont think the existing data is even remotely close to draw this kind of > conclusions. > > -- > > http://www.hitmen-console.org http://magicdisk.untergrund.net > http://www.pokefinder.org http://ar.pokefinder.org > > C makes it easy to shoot yourself in the foot; C++ makes it harder, but > when > you do it blows your whole leg off. > <Bjarne Stroustrup> > > > > Message was sent through the cbm-hackers mailing list > Message was sent through the cbm-hackers mailing listReceived on 2017-02-20 10:00:03
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