Overview

Orban's newest AM processor is powerful, user friendly, and comes with an impeccable pedigree.

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. They have proven that the “Optimod sound” attracts and keeps an audience even in the most competitive commercial environment.

The 9300 is very user-friendly. Its Quick Setup wizard walks you through the setup process. One-knob LESS-MORE control lets you customize the 9300's comprehensive factory presets easily. If you're an audio processing expert, you'll love the new Advanced Control parameters (accessible from 9300 PC Remote software) that allow you to customize the 9300's sound to your exact requirements.

Five-band Limiter with Distortion-cancelling Clippers: Multiband limiting and clipping are the most powerful techniques to achieve a consistently loud yet still very clean sound on the air. The audio is divided into five bands, then separately compressed and limited. Five-band limiting can operate far more quickly than a wide-band compressor without causing audible side effects. Five-band limiting increases the audio density in the 9300. Most of peak modulation control is performed within the five-band limiter, using Orban's patented multiband distortion-cancelling clipping. This eliminates the need for distortion-producing fast wide-band gain reduction.

Final Clipper: Provides final protection against peak over-modulation.

The 9300 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 and coverage). Except for newly designed parametric low-pass filters, the 9300's five-band compressor and clipper are identical to those in the 9200, but the 9300 adds a more powerful equalizer and advanced two-band AGC with window gating.

Input Conditioning Filter: An all pass phase scrambler makes peaks more symmetrical to reduce clipping distortion and to allow better control of loudness. The analog input is buffered and immediately followed by an analog-to-digital converter. All processing takes place in the digital domain.

High-pass Filter: Subsonic information has a negative effect on the processing, the transmiter and the receiver. It causes unnecessary gain reduction in the low frequency band of the limiter, reduces transmitter component life, increases power consumption and causes intermodulation distortion in the receiver's AGC. The 9300's high-pass filter effectively removes this unwanted subsonic information.

Low-pass Filter: Low-pass filtering limits bandwidth as required by the regulating authority. It is adjustable from 4.5 kHz (strict ITU-R Recommendation 328-5) to 9.5 kHz (NRSC) and its shape is parametric, allowing the user to trade off high frequency response against filter ringing. The 9300's output power spectrum is so tightly controlled that stations in Europe are able to operate with filtering as high as 6.0 to 6.5 kHz while still complying with ITU-R/EBU occupied bandwidth regulation! This greatly improves the received sound as compared to conventional 4.5 kHz filtering.

Two-Band Gated AGC: The automatic gain controller (AGC) compensates for operator gain-riding errors. This provides the five-band limiter with an uniform drive level, to achieve consistent sound on the air. Gating prevents noise rushup during pauses in program.

Receiver equalizer: Receiver equalization is a four-stage user-adjustable equalizer that compensates for the narrow bandwidth of receivers. High frequency equalization is necessary to compensate for the high frequency rolloff of receivers, effectively extending the receiver's high frequency response. Receivers often incorporate low frequency rolloff as well. Low frequency equalization provides similar compensation for bass frequencies. Also, the low frequency and midrange equalizers offer and effective tool to create your ”signature sound”.

If you wish to place level protection prior to your studio/transmitter link (STL), use an Orban studio level control system expressly designed for this purpose. (At the time of this writing, this is the Orban 6300 Multipurpose Digital Audio Processor.) The 6300 can be set up so that it substitutes for the broadband AGC circuitry in Optimod-AM, which is then defeated.

* The 9300 is a monophonic processor. If you need stereo processing and/or digital radio/netcast processing, Orban's state-of-the-art Optimod-AM 9400 is the ideal processor for you.

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