David, How come you never answer any of my questions about the
rubidium oscillator? I have asked you about it many, many times and have never
received any response from you. -Chuck
---- Original Message ----
From: "David Forbes" <[email protected]>
Sent: 4/10/2021 3:59:19 PM
To: "NeoNixie" <[email protected]>
Subject: X-IMail-SPAM-Connection Re: [neonixie-l] OT: How to convert
composite video into TTL?
I built a couple LED TV sets about ten years ago. I had to solve this
problem. I bought a sync separator chip for the first one, and a digitizer chip
for the other.
See the bottom of the page for schematics.
http://www.cathodecorner.com/satanvision/
On Sat, Apr 10, 2021, 6:04 AM jb-electronics
<[email protected]> wrote:
Thank you! I did some more digging and found
the service manual for the display (Panasonic TR-60S1A, see here:
https://www.opweb.de/english/company/Panasonic/TR-60S1A)
There is is a timing chart (see below). It
looks an awful lot alike NTSC to me, can somebody confirm?
Best wishes
Jens
On 2021-04-10 12:28 a.m., Adrian Godwin wrote:
It's easy enough to extract the sync
signals, as you've seen. It may not be particularly difficult to modify the TTL
input to analog, or to create a TTL level signal if you don't need a
grey-scale. On many general-purpose monitors like that they could often be
built for either standard - the microvitec Cub popular with the BBC
Microcomputer had that option.
But the critical thing is that
it runs at the right speed. CRT circuits are built around the line oscillator
which generates the horizontal scan AND the EHT voltage. It was only when
multisync monitors came along that the optimisation was split to reduce the
dependency. And if the frame frequency is wrong, you will often have problems
getting a full frame scan when you force it into sync.
So the first thing is that you
need to make sure the 8920 monitor ran at either PAL or NTSC rates so you can
choose a raspberry pi format to match. There's a good chance it's NTSC but
later monitors like the ones in the 54 series of digital scopes were more like
the IBM standards MDA and EGA (CGA was NTSC).
On Sat, Apr 10, 2021 at 4:28 AM
jb-electronics <[email protected]> wrote:
Hi all,
This is a bit of an off-topic
question, but I hope there will be
somebody here that can help. I
have bought a new-old stock monochrome
CRT for a HP Agilent 8920A,
basically this unit here:
https://www.ebay.com/itm/273930914548 .
It looks to me that it is just
a rebranded OmniVision 6" display:
http://www.omnivisionusa.com/Industrial-LCD-CRT-Monitors/replacement-crt/crt-monitors/6-inch-kit-.html
Now unfortunately it takes TTL
video as input. But I have a composite
source (a Raspberry Pi). How
can I convert composite into TTL? I
basically need to extract Hsync
and Vsync and feed it separately to the
unit, okay. There is an old
circuit here that does just that:
https://www.elektormagazine.com/magazine/elektor-198812/47485
But I know there are also
dedicated chips, like the GS1881:
https://www.mouser.com/datasheet/2/761/GS1881_GS4881_GS4981_Datasheet-769183.pdf
So basically here is my
question: before I dive into this any further,
is there any chance of success?
What is the optimal choice? Or is it
quite unlikely that I will be
able to convert the signals? I mean, even
if I manage to extract Hsync
and Vsync, is it likely to work?
I am sorry for the naive
question, but I am no expert on video signals,
and it would be nice if anybody
more experienced could chime in with a
few words of caution/experience.
Best wishes
Jens
--
You received this message
because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group
and stop receiving emails from it, send an email to
[email protected].
To view this discussion on the
web, visit
https://groups.google.com/d/msgid/neonixie-l/e0f398e8-24b1-952c-c998-0ddfbed6849e%40jb-electronics.de.
--
You received this message because you are
subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop
receiving emails from it, send an email to
[email protected].
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/CALiMYrvHCiXd3QSDmEJ%2Bpe3XgUutOC_C3yLFGxeOEo2bjtEAWw%40mail.gmail.com.
--
You received this message because you are subscribed to
the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving
emails from it, send an email to [email protected].
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/0b6843bf-8882-8a17-7c62-437ffc98a5ff%40jb-electronics.de.
--
You received this message because you are subscribed to the Google
Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to [email protected].
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/CAPbqtvdWTmhDEjMoQQvcS%2BBROe64k3S%3Dy9_g2%2Bn%2B_ACQDVyHJg%40mail.gmail.com.
--
You received this message because you are subscribed to the Google Groups
"neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web, visit
https://groups.google.com/d/msgid/neonixie-l/202104101513910.SM926892%40ADT-IM1.
