Luma discussions

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Luma discussions

boelle
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 <[hidden email]>:
On Monday 20 February 2017, 09:55:11 HÁRSFALVI Levente
<[hidden email]> wrote:
> On 2017-02-20 08:26, [hidden email] wrote:
> > On Monday 20 February 2017, 08:19:57 Gerrit Heitsch
> >
> > <[hidden email]> 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>



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Re: Luma discussions

HÁRSFALVI Levente-2
Of course you're free to do so, but (FYI) this is not an Internet forum.


On 2017-02-20 10:42, Bo Herrmannsen wrote:

> 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 <[hidden email] <mailto:[hidden email]>>:
>
>     On Monday 20 February 2017, 09:55:11 HÁRSFALVI Levente
>     <[hidden email] <mailto:[hidden email]>>
>     wrote:
>     > On 2017-02-20 08:26, [hidden email] <mailto:[hidden email]> wrote:
>     > > On Monday 20 February 2017, 08:19:57 Gerrit Heitsch
>     > >
>     > > <[hidden email] <mailto:[hidden email]>>
>     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
>     <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://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
>
>


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Re: Luma discussions

boelle
nope i know that :-D

but i know that thread hijacking is not a nice thing either :-D

that is the reason why i tried to change the subject so i can just delete the mails that has a subject i dont care for

but oh well, if it does not work i can live with it

2017-02-20 11:10 GMT+01:00 HÁRSFALVI Levente <[hidden email]>:
Of course you're free to do so, but (FYI) this is not an Internet forum.


On 2017-02-20 10:42, Bo Herrmannsen wrote:
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 <[hidden email] <mailto:[hidden email]>>:

    On Monday 20 February 2017, 09:55:11 HÁRSFALVI Levente
    <[hidden email] <mailto:[hidden email]>>
    wrote:
    > On 2017-02-20 08:26, [hidden email] <mailto:[hidden email]> wrote:
    > > On Monday 20 February 2017, 08:19:57 Gerrit Heitsch
    > >
    > > <[hidden email] <mailto:[hidden email]>>
    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
    <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://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 list

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