[SBE] Test patterns new and old

[Larry Bloomfield]

Andy et al:

If you go back into the Tech-Notes archives, I did a complete story on 
the Indian Head Test Pattern (IHTP) and explained what all its various 
elements are for. Where can I pick up my GM SUV?

I'm also, courtesy of Chuck Pharis, giving away a copy of the real IHTP 
(not the one with Chuck's head in it) at all of the Taste of NAB 2009 
presentations where there are 30 or more in attendance. :) 

Chuck also let me have a monoscope tube that I put on display so folks 
can see what the device was that generated the IHTP. As for the tone, 
many stations would air a 400 Hz tone with it, while others opted for 
the 1 kHz tone. Chuck has the IHTP for sale, if anyone is interested. 
www.pharis-video.com. He has one version of the IHTP that is in 16:9 and 
the Indian Head is colorized. :)

I also have some other tubes that I put on display at the Taste of NAB 
Road Show presentations for those who've never seen them:

The _*Monoscope*_ is a special form of cathode ray tube that was used to 
generate, rather than display, a video signal. Each tube was only 
capable of generating a single video signal, hence the name.  The 
Monoscope contains a formed metal target (in place of the phosphor 
coating) at its "screen" end. As the electron beam scans the target, a 
varying electrical signal is produced. This signal is an accurate image 
of the target and is used to produce test patterns like the classic 
Indian Head Test Pattern.
 
The _*Iconoscope*_ tube was patent in 1923 by Vladimir Zworykin, head of 
an RCA development team, but wasn't introduced until 1934. It was used 
for both live camera work and film chains. In 1946 it was replaced for 
live camera work by the Image Orthicon.
 
The _*I**mage Orthicon tube*_ - although developed in the 1939/1940 for 
the military, it wasn't released for civilian use until 1946 and saw 
service until 1968. It found service in both monochrome cameras and 
later on in color cameras as well.
 
The _*Vidicon*_ tube was developed in the 1950s at RCA by PK Weimer, SV 
Forgue and RR Goodrich as an alternative to the Image Orthicon for live 
camera work and the Iconoscope in film chains. It found service as both 
a color and monochrome camera pick-up device. It was used mostly in film 
chains.
 
The _*Plumbicon*_ tube (a registered trademark of Philips) was developed 
to replace the Image Orthicon tubes in color cameras. They had excellent 
resolution compared to Image Orthicons, but lacked the artificially 
sharp edges of IO tubes. CBS Labs invented the first outboard edge 
enhancement circuits to sharpen the edges of Plumbicon generated images.
 
All of these pick up devices have been technologically superseded by CCD 
and CMOS pick-up devices.

And don't forget the Order of the Iron Test Pattern.


LB

Andy Butler wrote:

> ...and for 10 extra points plus a chance at the luxurious GM SUV can 

> you list the purpose of each element in the "Indian Head" pattern?

>  

> ------------------------------------------------------------------------

> *From:* sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] *On Behalf Of 

> *Dennis Krumblis

> *Sent:* Friday, June 12, 2009 5:04 PM

> *To:* Vic Jester; sbe member discussion mail list

> *Subject:* Re: [SBE] WAGA Analog Sign Off w/ First CE

>  

>

>  

> ------------------------------------------------------------------------

> *From:* sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] *On Behalf Of 

> *Vic Jester

> *Sent:* Friday, June 12, 2009 2:21 PM

> *To:* sbe member discussion mail list; sbe member discussion mail list

> *Subject:* Re: [SBE] WAGA Analog Sign Off w/ First CE

>  

> Right - and then they should put an Indian Head with a 1kHz Tone on 

> the analog for a few days...

>

>  

>

> //seven.pairlist.net/mailman/listinfo/sbe

<snip>
-- 
*Larry Bloomfield, KA6UTC*
1980 25th St.
Florence, OR 97439
(541) 902-2424 (everything number)
*www.Tech-Notes.TV <http://www.Tech-Notes.TV>*
See you on the Taste of NAB Road Show
 
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