www.SteamPoweredRadio.Com July 10, 1986 Dear Broadcaster: Thank you very much for your interest in OPTIMOD-FMX. Enclosed is a package of information from both Orban and CBS. I ' m sure you will find it interesting. In our articles, we explain why the Orban OPTIMOD- FMX will be substantially different and better than units offering only the CBS "developmental" design. Until IC chips become available, FMX receivers will be very scarce. The latest information from CBS is that the first chips will roll off the line during the summer of 1987 , permitting receivers to be available just prior to Christmas 1987 . Orban expects to begin accepting orders for OPTIMOD- FMX in the Fall, with deliveries beginning late i n the year. As we have more information available, we will s end it to you. If you have any additional questions, feel free to call me on our toll- free number: 800- 227- 4498. Thank you for your confidence in OPTIMOD- FMX . Best regards , Howard Mullinack Marketing and Sales Manager Br oadcast Products www.SteamPoweredRadio.Com Orban Associates Inc. 645 Bryant Street San Francisco, CA 94107-1693 Main: (415) 957-1063 (Sales): (415) 957-1067 Telex: 17-1480 Cable: ORBANAUDIO Highlights D Increases stereo coverage area-to almost The Model 8150A OPTIMOD-FMX is a complete, that of the mono coverage area- self-contained stereo generator. It combines a newly­ for receivers equipped with FMX designed ultra-high-performance stereo encoder with the Orban FMX compander and subcarrier generator, decoders. including remote control facilities and an integral power D Fully compatible with non-FMX equipped supply. receivers. It installs directly below OPTIMOD-FM Models 8000A, 8100A, and 8100A/1, and can work with the □ Orban's proprietary program-dependent Studio Chassis and/ or XT Six-Band Limiter. Your FMX control circuitry achieves optimum current OPTIMOD can be easily adapted for FMX. Just noise reduction without danger of add an easy-to-install interface connector. And OPTIMOD-FMX can be used with nearly any audio overmodulation. processor that offers a peak-controlled output signal □ Works with OPTIMOD-FM of any tightly bandlimited to 15kHz and has output vintage, and some other audio attenuators. processors. As development and on-air testing continues, O rban will release further progress information. D Projected delivery: Late Fall 1986. o,ban Orban Associates Inc. 645 Bryant Street, San Francisco, CA 94107 (800) 227-4498 or (415) 957-1067 Telex 17-1480 OPTIMOD" is• registtred trademark of Orban Assoclatts Inc. FMX t M. is a registfftd trademark of CBS. Inc. ORBAN OPTIMOD-FMX 800038-000-02www.Stea 5186mPoweredRadio.Com ORBAN TECHNICAL NOTES ON FMX - #1 by Howard Mullinack FMX improves stereo coverage The advantages of FMX become less and less apparent as more processing ls FM stereo reception suffers Crom slgnlficanlly increased noise as compared used to load the composite more and more heavily. If the composite always to mono reception-typically 23 to 26dB. This noise Increase restricts the looks like It has been shaved with a buzzsaw, there won't be any room for coverage area of acceptable stereo reception to approxlmately one-fourth the the added subcarrier. The FMX compressor will stay In its "reentrant mode" coverage area of acceptable mono reception. FMX was developed by CBS much of the time, and little or no noise reduction will be avalJable (except Technology Center and the National Association of Broadcasters in an attempt possibly when the announcer pauses for air). Of course, with high modula­ to solve this problem. tion levels, the noise will be somewhat less apparent. Stations equlpped with FMX can increase their stereo coverage area-up to OPTIMOD-FMX-our approach about that of their mono coverage area-for lbose receivers equipped wilb It's dear that the design of a " real-world" FMX compressor ls quite a com­ P!tfX decoders. Yet FMX broadcasts are completely compatible with non-FMX plex endeavor. FMX encoders will be highly differentiated according to the receivers, which will continue to receive stereo or mono normally. skllls of the various manufacturers. How FMX works At Orban, four goals FMX ls a compandlng system: The L-R audio (which ls the source of the were foremost In the noise increase in stereo) is compressed before transmlsslon and expanded at design of the OmMOD­ the receiver. FMX Stereo Generator: (1 ) OPTIMOD-FMX : To assure compatabiUty with existing radios, the L-R stereo subcarrier Is It cannot produce over­ transmltted at 38kHz in the normal manner. In addition, a second L-R subcar­ modulatlon; (2) the on-alr AN INTRODUCTION rier (the FMX subcarrier) is transmltted at the same frequency In quadrature sound must not suffer from audible loss of (90° out of phase) with the original subcarrler. The FMX subcarrler Is com­ pressed, and Includes a JOHz pilot tone. loudness; (3) compression characteristics that produce audible processing artifacts will not be accept­ In the FMX-equlpped receiver, both the "original L-R" and "FMX" subcar­ able; and (4) the design must not degrade SCA performance. riers are detected. The receiver sums the "original L-R" and " FMX" signal, and then expands the audio on this sum to match the dynamlcs of the Real-world on-alr testing "original L-R" audio. Since the receiver uses the "original L-R" as a ref­ So far, FMX has been on-air tested by CBS at only a few "public" stations erence, it can accurately reconstruct the FMX signal without the FMX using very conservative processing. We feel that If FMX ls to be successful, it generator's having to maintain precisely defined compression characteristics. must work with all types of formats and processing preferences, with various This Is called " adaptive expansion": the expander adapts to match a wide exciters and STI.s, and on stations with and without SCA. It must not variety of compression characteristics. significantly increase the deleterious effects of multipath. The noise reduction Is achieved when the FMX L-R audio Is expanded: low If FMX encoders are released prematurely, without thorough research of level signals, and the noise, are reduced in level. Typically, up to 20dB of potential drawbacks and extensive on-air testing to assure that those draw­ noise reduction can be achieved. backs are overcome, FMX will be doomed to failure. First impressions are lasting impressions. We are now beginning our own series of extensive on-air FMX compression characteristics vs. "real-world" radio tests. CBS, In their design of FMX, Introduced a "developmental" compressor to permlt initial field trials and to prove the basic FMX principles. But the com­ Availability of FMX receivers pression characteristics of this " developmental" compressor are not ap­ IC manufacturers are just starting development of FMX decoder chips, so plicable to many stations. Fortunately, " adaptive expansion" allows Orban to receivers for the mass market will not be available before mld-1987. Two optimlze the compressor characteristics of FMX while maintaining full high-end hl-fi manufacturers, NAO and Apt, expect to have a limlted supply of recovery of the original signal on standard and FMX-equipped receivers. receivers available later this year, with FMX implemented using discrete circuitry. The first area of concern In the design of the OPTIMOD-FMX compressor is ovemwduJaffon. Under certain sound field conditions, the CBS Availability of OPTIMOD-FMX "developmental" compressor can create continuous overmodulation-not Orban may be first to market, but only If we have a finely tuned product just overshoots-of up to 26 % . that will satisfy the needs of our customers. The necessary design and field testing must be done carefulJy, and wllJ take some time. Another factor ls loudness and audio processing. The FMX system adds an additional subcarrier (and additional modulation) 10 the composite signal. Normally, modulation must be reduced to accommodate an additional subcar­ rier. The CBS " developmental" compressor has a reentrant characteristic: As the level of the "original L--R" subcarrler increases toward 100 % modula­ tion, the level of the " nlX" subcarrier decreases. With full modulation of the • OfTIJIOO Is ■ r,gblttl'd lrtdetrwll of Orlwl Assodsl,s Inc. 00 Is ■ r,gtsleml 1..itmvt ol CBS In(, "original" L-R subcarrler, the "FMX" subcarrler actually disappears, with all Orban Associates Inc., 645 Bryant Street, San Francisco, CA 94107 of the benefits of f/llX disappearing with lt. (800) 227-4498 or (415) 957-1067 Telex 17-1480 o,ban 920008-000-01 5186 www.SteamPoweredRadio.Com ORBAN TECHNICAL NOTES ON FMX - #2 by Robert Orban FMX111 ls an FM stereo compandiog system which offers up to 20dB noise reduc­ ponents. OPTIMOD-FMX Is designed to plug directly Into an OPTIMOD-FM of any tion In stereo mode, yet Is compatible with exlstlng receivers. Developed jointly by vintage (Including the old 8000A) and to operate without further adjustment Emil Torick of CBS Technology and Tom Keller or NAB, It promises the first funda­ OPTIMOD-FMX can also mental Improvement In FM stereo technology since the system was approved almost be used with nearly any 25 years ago. audio processor equipped Nevertheless, to assure the success of FMX In the mass market, there are a with output attenuator con­ number of potential pitfalls which must be addressed. Some of these Include over­ trols, and with a peak­ modulation control, noise modulation effects, multipath distortion, system perfor­ controlled output signal mance In the automotive environment, and the effects of audio processing. Orban is that Is tightly bandlimlted taking all of these Imo account In the development of our FMX generator. to 15kHz. (Older FM peak Thanks to the novel concept or "adaptive expansion" In th.e receiver, an FMX llmlters manufactured by receiver can adapt to a wide variety of transmission compression characteristics.