Optimod-AM 9300 Audio Processor
Orban’s powerful and user friendly AM processor.
Orban’s all-digital 9300 Optimod-AM audio processor can help you achieve the highest possible audio quality in monophonic AM shortwave, medium wave and long wave broadcasts. Optimod-AM delivers louder, cleaner, brighter, FM-like audio with an open, fatigue-free quality that attracts listeners and holds them. Because all processing is performed by high-speed mathematical calculations within Motorola DSP56367 digital signal processing chips, the processing has cleanliness, quality and stability over time and temperature that is unmatched by analog processors.
Optimod 9300 is descended from the industry-standard 9100 and 9200 Optimod-AM audio processors. Thousands of these processors are on the air all over the world. For more then 30 years, Orban has proven that the “Optimod sound” attracts and keeps an audience even in the most competitive commercial environment. Optimod-AM was designed to deliver a high quality FM-like sound to the listener’s ear by pre-processing for the limitations of the average car or table radio (while avoiding audible side effects and compromises in loudness or coverage). Because such processing can make audible many defects ordinarily lost in the usual sea of AM mud, it is very important that the source audio be as clean as possible. The 9300 is very user-friendly. Its Quick Setup wizard walks you through the setup process. The One-knob LESS-MORE control lets you customize the 9300’s factory presets easily. If you’re an audio processing expert, you’ll love the Advanced Control parameters (accessible from 9300 PC Remote software) that allow you to customize the 9300’s sound to your exact requirements.
Making the Most of the AM Channel
Optimod-AM rides gain over an adjustable range of up to 25dB, compressing dynamic range and compensating for operator gain-riding errors and for gain in- consistencies in automated systems. Optimod-AM increases the density and loudness of the program material by multiband limiting and multiband distortion canceling clipping, improving the consistency of the station’s sound and increasing loudness and definition without producing audible side effects. Optimod-AM precisely controls peak levels to prevent over-modulation. Optimod-AM compensates for the high- and low- frequency rolloffs of typical AM receivers with a fully adjustable program equalizer providing up to 20dB of high-frequency boost (at 5 kHz) without producing the side effects encountered in conventional processors. This equalizer can thus produce extreme pre-emphasis that is appropriate for very narrow-band radios. Optimod-AM ‘s fully parametric low- and mid-frequency equalizers allow you to tailor your air sound to your precise requirements and desires. Optimod-AM also fully supports the NRSC standard pre-emphasis curve.
Optimod-AM comes with a wide variety of factory presets to accommodate almost any user requirement. A single LESS-MORE control easily modifies any factory preset. The user (via FULL CONTROL) can further customize the presets, and these can be stored and recalled on command. Advanced Control (accessible from the PC Remote application) facilitates detailed sound design using the same controls that were available to the factory programmers. OPTIMOD-AM controls the transmitter bandwidth as necessary to meet government regulations, regardless of program material or equalization. Optimod-AM’s high-frequency bandwidth can be switched instantly in 500Hz increments between 4.5 kHz and 9.5 kHz. The lower cutoff frequencies meet the output power spectral density requirements of ITU-R 328-5 without further low- pass filtering at the transmitter, while the 9.5 kHz filter meets the requirements of the NRSC-1 standard (North America). The 5.0 kHz filter makes the analog AM bandwidth compatible with HD-AM transmission. The low-pass filters have parametric cutoff shapes, allowing you to trade off filter ringing against frequency response flatness. Optimod-AM compensates for inaccuracies in the pulse response (tilt, overshoot, ringing) of transmitters and antenna systems with a powerful four- parameter transmitter equalizer. A built-in square-wave generator makes adjustment easy. Four sets of equalizer parameters can be stored and recalled, al- lowing you to program day and night variations for two transmitters. Two mono analog outputs and one AES3 output accommodate as many as three transmitters.
Optimod-AM is usually installed at the transmitter, replacing all processing normally employed at the transmitter site, including compressor, protection peak limiters, clippers, and high- and low-pass filters normally included within the transmitter.
Optimal Control of Peak Modulation Levels
The audio processing circuitry in Optimod-AM produces a waveform that is precisely peak-controlled to prevent over-modulation, and is low-pass filtered to protect adjacent channels and to conform to government regulations. Low-pass filters (including anti-aliasing filters in digital links), high-pass filters, transformers, distribution amplifiers, and long transmission lines can all cause the above criteria to be violated, and must be tested and qualified. It is clear that the above criteria for optimal control of peak modulation levels are met most easily when the audio processor directly feeds the transmitter. While Optimod-AM’s transmitter equalizer can mitigate the effects of group delay and frequency response errors in the signal path, an accurate path will still achieve the best results.
Controllable and Adjustable
An LCD and full-time LED meters make setup, adjustment and programming of OPTIMOD-AM easy — you can always see the metering while you’re adjusting the processor. Navigation is by dedicated buttons, soft buttons (whose functions are context-sensitive), and a large rotary knob. The LEDs show all metering functions of the processing structure (Two-Band or Five-Band) in use. Optimod-AM contains a versatile real-time clock, which allows automation of various events (including recalling presets) at pre-programmed times.
A Bypass Test Mode can be invoked locally, by remote control (from either the 9300’s GPI port or the 9300 PC Remote application), or by automation to permit broadcast system test and alignment or “proof of performance” tests. Optimod-AM contains a built-in line-up tone generator that offers sine, square, and triangle waves, facilitating quick and accurate level setting in any system.
Optimod-AM’s software can be upgraded by running Orban-supplied downloadable upgrade software on a PC. The 9300 can be remote-controlled by 5-12V pulses applied to eight pro- grammable, optically isolated “general-purpose interface” (GPI) ports. 9300 PC Remote software runs under Windows Vista, 7, 8, 8.1, and 10. It communicates with a given 9300 via TCP/IP over modem, direct serial, and Ethernet connections. You can configure PC Remote to switch between many 9300s via a convenient organizer that supports giving any 9300 an alias and grouping multiple 9300s into folders.