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Old 30th Dec 2019, 4:49 pm   #1
G6Tanuki
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Default Interesting article on Hazeltine Corporation.

Though in many ways a 'forgotten name'. Hazeltine - through their "Hazelpat" division - were rather significant in the development of radio in the 20th century... see https://www.wshu.org/post/hazeltine-silent-contributor
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Old 30th Dec 2019, 7:11 pm   #2
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Default Re: Interesting article on Hazeltine Corporation.

I've got an early 70's Hazeltine model 2000 computer terminal somewhere, rather a nicely made thing.

Ironic that they're now owned by BAE.
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Old 30th Dec 2019, 7:53 pm   #3
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Default Re: Interesting article on Hazeltine Corporation.

Yes, in times-past I was quite familiar with h1500 and h2000 as entries in the /etc/termcap file and the associated "setenv TERM h1500" csh fun on 1980s/1990s Unix-and-derivative systems.

Hazeltine were, as the article notes, one of the 'quietly pervasive' tech companies of the last century, in the same way as a certain Mr. Lear (famous for involvement in the LearJet but much more deeply-influential for having developed the 8-track audiotape-cartridge - and the Lear-Siegler ADM3A ASCII-terminal).
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Old 31st Dec 2019, 1:06 pm   #4
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Default Re: Interesting article on Hazeltine Corporation.

I believe Hazeltine and CBS were both developing a colour tv system in early 1940 and got into a patent application dispute.
J C Wilson ex - Baird and Ferranti developed an early colour tv system whilst working for the Hazeltine corp but was suffering from Hodgkins disease, from which he died. Peter Goldmark of CBS was developing field-sequential colour simultaneously and was considered to have prior art
It would appear that Hazeltine were either very sloppy in their patent application or didn’t fully appreciate the value of Wilson's work. Perhaps Steve (Synchrodyne) would have some better source material?

Eddie
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Old 1st Jan 2020, 9:05 pm   #5
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Default Re: Interesting article on Hazeltine Corporation.

Unfortunately I can’t help much with this item. I suspect that it could be difficult to find much information on the Hazeltine field sequential colour television system.

For example, it was not included in the list of colour TV systems included in Fink, “Television Standards and Practice”, 1943:

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As a corollary, it was not mentioned in Fink, “Television engineering”, 2nd edition, 1952:

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Fink included a brief history of colour TV systems in “Color Television Standards”, 1955, (which was primarily about the NTSC system) but there was no mention of the Hazeltine field sequential system.

Fink was probably the leading chronicler of American TV systems development of that era (and a very lucid technical writer). Thus one may wonder if, after CBS priority had been established, Hazeltine suppressed the release of information about its system.

The CBS field sequential system was described in an article in “Electronics” magazine 1940 October. An initial search over the same timeframe did not find a comparable article for the Hazeltine system in that magazine or other likely candidates.


Cheers,
Attached Files
File Type: pdf Fink TV Stds & Practice p.30,31.pdf (737.4 KB, 51 views)
File Type: pdf Fink TVE 2nd p.487.pdf (146.4 KB, 45 views)
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Old 1st Jan 2020, 9:10 pm   #6
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Default Re: Interesting article on Hazeltine Corporation.

Nonetheless, Hazeltine was evidently not deterred, and made significant contributions to what became the NTSC system, as shown in this excerpt from Fink, “Color Television Standards”:

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Item (3) turned out to be quite important. Originally the NTSC had proposed equal bandwidth colour difference signals, necessarily both vestigial sideband, with phase alternation to avoid the crosstalk that arose from the demodulation of vestigial sideband QAM signals. The phase alternation was found to cause edge flicker, so was abandoned. The crosstalk was then avoided by making one of the colour difference signals double sideband and so necessarily narrowband.

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These Hazeltine contributions were discussed in an article in “Electronics” 1951 February, “Comparative Analysis of Color TV Systems”.


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File Type: pdf Fink CTV p.22.pdf (178.3 KB, 46 views)
File Type: pdf Fink CTV p.35.pdf (189.8 KB, 42 views)
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Old 1st Jan 2020, 9:31 pm   #7
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Default Re: Interesting article on Hazeltine Corporation.

It may also be noted that the Fremodyne simple FM receiver of 1947 was a Hazeltine development.


Cheers,
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Old 1st Jan 2020, 11:10 pm   #8
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Default Re: Interesting article on Hazeltine Corporation.

And of course the Kahn- Hazeltine AM stereo system https://en.wikipedia.org/wiki/AM_stereo#Kahn-Hazeltine
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Old 2nd Jan 2020, 12:41 am   #9
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Default Re: Interesting article on Hazeltine Corporation.

The Kahn-Hazeltine AM stereo system struck me as being a bit awkward. Although referred to as “ISB”, it was not true ISB, nor was it C-ISB. Kahn had done prior work on compatible single sideband (CSSB) transmission, and to a first approximation, it looked as if the AM stereo system was a back-to-back pair of CSSB channels. CSSB involved a phase modulation “fudge factor”, as did the stereo system, and it wasn’t clear to me that this “fudge factor” could be precisely “undone” at the receiving end. In comparison, the other AM stereo systems were all suitable for accurate decoding at the receiving end.

Kahn seems to have been the prime mover for the “ISB” AM stereo system; I am not sure what was the Hazeltine contribution. However, back in the 1950s, Hazeltine developed the so-called “quadricorrelator” circuit for use in colour TV subcarrier demodulation, valve-based. This could also have been used as the basis for a quadrature or ISB AM demodulation. So perhaps Hazeltine provided demodulation expertise.


Cheers,
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Old 2nd Jan 2020, 11:26 am   #10
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Default Re: Interesting article on Hazeltine Corporation.

I hadn't associated Hazeltine with the US CTV standards but looking back, it does make sense.

From memory: in the 50s Hazeltine had (in conjunction with Sylvania?) patented a sort-of colour CRT display with two phosphors - one green and one yellow.

IBM developed something very similar (though using a different electron-gun strategy for illuminating the 2 phosphors) for their mid-1950s AN/FSQ-7 "Semi Automatic Ground Environment" missile-tracking computer for the US Military [at the time - and for a decade or so - this was the world's biggest computer system] - the displays used some really-large CRTs with a long-persistence green phosphor for displaying radar-tracks, and a short-persistence yellow phosphor for realtime on-screen text/symbols identifying what the track was (speed, altitude, whether it's one-of-ours or one-of-theirs), along with the first use of 'light pens' for interaction..

When Hazeltine/Sylvania got to hear about this they were not so happy - and quietly (because the whole SAGE thing was understandably considered top-secret) initiated legal action. I believe the case was tried in secret and 'sealed' under some 99-year-rule or other, but compensation for patent-breach did get exchanged, in Hazeltine's favour.

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Old 3rd Jan 2020, 12:33 am   #11
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Default Re: Interesting article on Hazeltine Corporation.

Quote:
Originally Posted by Synchrodyne View Post
Unfortunately I can’t help much with this item. I suspect that it could be difficult to find much information on the Hazeltine field sequential colour television system.
Possibly the Hazeltine sequential system at interest was that described in US Patent 2,375,966?

At first glance it Iooks to have been quite complex, and involved rotating mirrors.


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File Type: pdf US2375966 Hazeltine Sequential Color TV.pdf (1.51 MB, 58 views)
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Old 3rd Jan 2020, 2:08 am   #12
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Default Re: Interesting article on Hazeltine Corporation.

Quote:
Originally Posted by Synchrodyne View Post
Unfortunately I can’t help much with this item. I suspect that it could be difficult to find much information on the Hazeltine field sequential colour television system.
Possibly the Hazeltine sequential system at interest was that described in US Patent 2,375,966?

US2375966 Hazeltine Sequential Color TV.pdf

At first glance it Iooks to have been quite complex, and involved rotating mirrors.


[QUOTE=Synchrodyne;1203906]Kahn seems to have been the prime mover for the “ISB” AM stereo system; I am not sure what was the Hazeltine contribution./QUOTE]

It would appear that the Hazeltine contribution is encapsulated in US Patent 4,589,127, which followed a series of Kahn patents. Basically Hazeltine offered simpler processing at the transmitting and receiving ends, although overall, the system was still quite complex.

US4589127 Hazeltine ISB Stereo.pdf

Perhaps the complexity is explained by the fact that one somewhat offbeat facility that Kahn was keen on was the ability to receiver in stereo using two AM receivers, one off-tuned for the lower sideband and the other off-tuned for the upper sideband. For this to work each sideband would have to look like a CSSB transmission to the respective receivers. Probably C-ISB would not have worked so well in this role.


Quote:
Originally Posted by G6Tanuki View Post
I hadn't associated Hazeltine with the US CTV standards but looking back, it does make sense.
Hazeltine’s contribution to the development of the NTSC system does seem to have been major, judging by US Patent 2,774,072. That looks like it was the main bridge between the RCA dot-sequential proposal and a workable system. Additionally Hazeltine did a lot of work in receiver circuitry, particularly in respect of colour synchronization and demodulation.

US2774072 Hazeltine CTV System.pdf


Cheers,
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Old 3rd Jan 2020, 3:55 pm   #13
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Default Re: Interesting article on Hazeltine Corporation.

Quote:
Originally Posted by Synchrodyne View Post
Quote:
Originally Posted by G6Tanuki View Post
I hadn't associated Hazeltine with the US CTV standards but looking back, it does make sense.
Hazeltine’s contribution to the development of the NTSC system does seem to have been major, judging by US Patent 2,774,072. That looks like it was the main bridge between the RCA dot-sequential proposal and a workable system. Additionally Hazeltine did a lot of work in receiver circuitry, particularly in respect of colour synchronization and demodulation.
Interesting to see that the name on the patent is Loughlin - he was also the guy who invented the Fremodyne.
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Old 3rd Jan 2020, 9:26 pm   #14
John KC0G
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Default Re: Interesting article on Hazeltine Corporation.

Much of the work of the Hazeltine Corporation (HC0 was documented by Harold Alden Wheeler who was working for Alan Hazeltine before the Corporation was founded in 1924. Wheeler worked for HC until 1946, and founded Wheeler Labs in 1947. HC took over Wheeler Labs in about 1959. Wheeler later became Chairman and stepped down from that role in 1977, and as chief scientist in 1987.

Some useful sources of history are:

1. H. A Wheeler, Hazeltine, the Professor, Hazeltine Coropration, 1982

2. H. A. Wheeler, The Early Days of Wheeler and Hazeltine Corporation - Profiles in Electronics, Hazeltine Corporation, 1982
This covered the period up to WW2, but the biography section includes later details of the people described

3. H. A. Wheeler, Hazeltine Corporation in World War II, Ventura , CA, 1993. Again the biography section extends beyond the time frame of the main work of the book.

4. H. A. Wheeler, Wheeler Monographs, Vol. 1, Wheeler Laboratories, 1953.
Wheeler wrote 22 monographs and the first 11 were published in Volume 1. I think that the rest were published in Volume 2 , but I have never seen a copy.

5. Harold A. Wheeler, an oral history conducted in 1985 by Ronald R. Kline, IEEE History Center, Hoboken, NJ, USA.
https://ethw.org/Oral-History:Harold_A._Wheeler_(1985)

6. Harold A. Wheeler: An Interview conducted by Rik Nebeker, IEEE History Center, 29-31 July 1991
https://ethw.org/Oral-History:Harold_Wheeler_(1991)

Wheeler gives bios for Bernard D. (Barney) Loughlin in both #2 and #3. In the latter he describes his major contributions to color TV, ie Shunted Monochrome (US2,774072), Constant Luminance (US2,773,929) and later Color Phase Alternation (US2,943,212). These patents provided a substantial fraction of the Hazeltine income until they expired. See: https://www.nae.edu/188909/BERNARD-D-LOUGHLIN-19171988
Loughlin was given the first IRE Vladimir Zworykin Award in 1952.

There is some fascinating material, which is new to me, on the Fremodyne at http://members.iinet.net.au/~cool386...ne/fremo3.html. It lists the Hazeltine patents on super-regenerative receivers. To the list of references should be added:
A. Hazeltine, D. Richman and B.D. Loughlin, "Super-Regenerator Design", Electronics, September 1948, pp 99-. This can be found at americanradiohistory.com

Strangely, these is a current thread on FM regens at https://www.vintage-radio.net/forum/...d.php?t=162459

John
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Old 3rd Jan 2020, 10:06 pm   #15
G6Tanuki
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Default Re: Interesting article on Hazeltine Corporation.

Hey! Thanks for posting those other links!

I love following these sorts of technical trails....
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Old 4th Jan 2020, 9:36 pm   #16
John KC0G
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Default Re: Interesting article on Hazeltine Corporation.

You might want to be careful what you wish for...

See https://ethw.org/Archives:Sparks_of_...ing_Excellence for an online version of the book "Sparks of Genius" by Nebeker, and specifically the chapter relating to Wheeler.

Back to colour TV, this retrospective paper by Loughlin on the development of TV from the RCA system to NTSC is interesting. See: http://www.earlytelevision.org/pdf/r..._hazeltine.pdf

For a book of recollections about Wheeler Laboratories, see: http://arlassociates.net/1999WheelerBook.pdf

John

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Old 4th Jan 2020, 9:48 pm   #17
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Default Re: Interesting article on Hazeltine Corporation.

Very interesting - I had only known of Hazeltine as manufacturers of computer terminals with stunningly unreliable keys, back in the late seventies.
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Old 4th Jan 2020, 11:08 pm   #18
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Default Re: Interesting article on Hazeltine Corporation.

John, thanks very much for posting all of those links.

This one in particular is a real gem:

Quote:
Originally Posted by John KC0G View Post

Back to colour TV, this retrospective paper by Loughlin on the development of TV from the RCA system to NTSC is interesting. See: http://www.earlytelevision.org/pdf/r..._hazeltine.pdf

Cheers,
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