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By
Robert Orban
Chief Engineer
San Leandro, CA
In "Composite Processing Remains Hot" (Radio World, May 29, 1996) Eric
Small wrote "The reign of the Volumax ended when Orban and I developed the Optimod FM
integrated processor and generator." This statement cries out for- amplification and
a trip down memory lane into the mists of broadcast history, ca. 1974.
In 1972; I was helping out
an old college friend at his Class-A FM in Los Altos, Calif. I built him a custom stereo
limiter, which used clipping as the means of final peak control. A mystery arose when
peaks that were clearly well controlled at the studio produced egregious overmodulation on
the air as read on the station's Belar FMM-1 modulation monitor.
A call to Arno Meyer at
Belar revealed the reason: The 15 kHz low-pass filters in the Collins stereo generator
were overshooting and ringing. I took a scope up to the transmitter and, sure enough, Arno
was right that was exactly what was happening.
Two years later I decided to
design a broadcast compressor/limiter as Orban Associates' next product. I remembered the
problems I had encountered with the stereo generator's low-pass filters.
It occurred to me that a
good solution would be to design non-overshooting low-pass filters and to package the
compressor, limiter, high-frequency limiter, filters and stereo generator together, as a
system. I proceeded to design and prototype a single channel of this processing and build
it on a perf-board.
I had been working with Eric
Small on the tests of the Nippon/Columbia quadraphonic broadcast system for FM, so it
seemed logical that I take this prototype to him. We hooked it up to his Belar and he was
very impressed. He had never seen the modulation meter swing so high with no peak flasher
activity.
I told him that the way the
system had to work was that two channels of this processing had to be packaged with a
stereo generator so that any circuit elements that could cause overshoot would be
contained within the system and would thus be controllable.
After thinking about it for
a bit, he agreed, and said that he wanted to get involved with the marketing and
development of the product that was to become Optimod-FM Model 8000A.
Eric's primary contributions
to the development were three: He consulted on the user interface, he helped design the
packaging so that the unit would be RFI-resistant and he interfaced with the FCC to ensure
that the unit could legally be connected to transmitters (by making the unit's output look
like the output of a composite STL because these had already gotten the FCC's OK).
However, the circuit design,
systems design and even the "Optimod" moniker were my creations, and I am the
sole inventor named on the relevant patent (U.S. #4,103,243).
After my business partner
John Delantoni and I completed design and packaging of the production 8000A in 1975, Eric
Small and Associates was engaged to market and promote the unit for a period of two years.
Eric did a fine job in communicating the advantages of the
systems approach to processing, and made sure that the unit got into the hands of the
industry's movers and shakers early on. As part of the marketing effort, he made a
number of measurements demonstrating quantitatively that the new system's approach
achieved up to 3 dB higher on-air loudness than the old technology, while controlling peak
modulation far more consistently. Optimod-FM was up and running and Orban started a period
of rapid growth.
The 8000A was manufactured
until 1980, when it was replaced by the 8100A, which ultimately became the best-selling FM
processor in the history of the industry and is still being manufactured today.
After the expiration of
Eric's two-year contract, Delantoni and I decided that Orban had grown large enough to
move sales and marketing in-house where it could be more tightly coupled to our management
structure. Eric moved on to other endeavors, eventually founding Modulation Sciences.
Robert Orban
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