Equalizing pulse needed?

[C. Balci]

Hello,

As far as i know, there is no need for many (6 before and 6 after
field synch)equalizing pulses in RS170 video anymore. Does any of you
know sources (preferable official) supporting this claim?

Regards,

Balci

 

And after 60 years and countless units built you need to change this
because? If you have any intention of interfacing with
commercial/consumer units, you'll find out in short order that needed
or not, they're needed.
GG

 

[tlbs]

C. Balci wrote:

Hello,

As far as i know, there is no need for many (6 before and 6 after
field synch)equalizing pulses in RS170 video anymore. Does any of you
know sources (preferable official) supporting this claim?

Regards,

Balci

Why would you think they are not necessary?

I just completed a video encoder/decoder design and the target display
devices (1 NTSC and 1 Component video) both required EQ pulses. The
NTSC monitor was very "forgiving" and would sort-of lock to anything
that resembled sync., but I wouldn't trust that any other monitor would
do the same.

I haven't heard of any changes to the RS-170 standard, or any new NTSC
specs lately.

 

[C. Balci]

"tlbs" <tlbs101@excite.com> wrote in message news:<1112813779.584913.58300@o13g2000cwo.googlegroups.com>...

C. Balci wrote:
Hello,

As far as i know, there is no need for many (6 before and 6 after
field synch)equalizing pulses in RS170 video anymore. Does any of you
know sources (preferable official) supporting this claim?

Regards,

Balci

Why would you think they are not necessary?

I just completed a video encoder/decoder design and the target display
devices (1 NTSC and 1 Component video) both required EQ pulses. The
NTSC monitor was very "forgiving" and would sort-of lock to anything
that resembled sync., but I wouldn't trust that any other monitor would
do the same.

I haven't heard of any changes to the RS-170 standard, or any new NTSC
specs lately.

No standard change, only device capabilities increased. See

http://groups.google.com/groups?q=%22eia+industrial+electronics+tentative%22&hl=tr&lr=&rls=GGLB,GGLB:1970-01,GGLB:en&selm=120926%40sun.Eng.Sun.COM&rnum=2

 

[tlbs]

While the NTSC monitor I output video to was very forgiving, the RGB
display was not. The RGB display (the main target of the video
encoder/decoder system) would *not* lock (sync-on-green BTW) if the
signal was not within the specification of RS-170 -- including EQ
pulses. I tried to get the RGB display to work without them, but it
would not.

So as you pointed out... while there indeed, some devices that function
without EQ pulses, there are obviously still some devices that require
RS-170/NTSC as-written.

The video encoder/decoder chips I used are from Analog Devices
(ADV7179, ADV7181a). They are not obsolete. They allow you to
manually "play" with the synchronization over a wide range of
possibilities, but the chipset also has the proper NTSC as a preset
standard (as well as PAL, SECAM, and variants of the 3). If Analog
Devices still produces chipsets that produce video according to the
standards (TI and others do, also), that tells me that things like EQ
pulses are still needed.

I also built composite sync inside an FPGA, including the EQ pulses
(for possible future upgrades to this system).