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Transmission Transmission

Audio Processors



From: Orban

-User-Friendly Interface
-Flexible Configuration
-5518 PC Remote software
-LCD and full-time LED meters

The Orban Optimod 5518 FM is a superb high-quality stand-alone stereo encoder combining look-ahead and band-limited clipping techniques to control STL-induced overshoots while minimizing artifacts. Orban’s all-digital 5518 FM Stereo Encoder operates at 64 kHz to 512 kHz sample rates and offers lowpass filtering, left/right-domain overshoot limiting, composite limiting, diversity delay and an ITU BS.412 multiplex power controller.The 5518 is compatible with all Orban OPTIMOD-FM processors, including the 2200, 2300, 5300, 5500, 8000, 8100, 8200, 8300, 8400, 8500 and 8600.It also compatible with most other processor brands.An LCD and full-time LED meters make setup, adjustment and programming of the 5518 easy — you can always see the metering while you are adjusting the processor. Navigation is by dedicated buttons, soft buttons (whose functions are context-sensitive), and a large rotary knob.

The 5518’s patented “Half-Cosine Interpolation” composite limiter provides full spectral protection of subcarriers and RDS/RBDS regardless of the amount of composite limiting.The built-in, defeatable ITU BS.412 multiplex power controller acts on all outputs to meet even the most stringent European government regulations.A 10 MHz frequency reference input allows the stereo pilot tone frequency to be locked to GPS or another high-accuracy frequency standard.This improves the performance of single-frequency networks in areas where coverage of the transmitters overlaps.The 5518 uses the same preset logic as other OPTIMOD-FMs and should be familiar to users of the OPTIMOD-FM family of products.Because the 5518 is a dedicated stereo encoder, it comes with only one Factory Preset, which allows you to set up the parameters of the stereo encoder. Normally, when you have finished setting up the 5518 by editing its Factory Preset, you will then save the result as a User Preset. You can save many different customized settings as different User Presets.

Input/Output Configuration: The 5518 simultaneously accommodates:

Digital AES3 left/right inputs and outputs.
Analog left/right inputs and outputs.
Composite stereo outputs.

The left/right analog and digital outputs can be flat or pre-emphasized and emit the output of the left/right overshoot limiter. This allows the peak-controlled output of the 5518 to drive an STL conveying audio to a second FM transmitter, translator or booster.A sync reference input that can accept 10 MHz or 1 x wordclock (32, 44.1, 48, 88.2 and 96 kHz) and lock the digital output sample rate and the 19 kHz pilot tone frequency to this input.The 5518 can be remote-controlled by 5 to 12 V pulses applied to eight programmable, optically-isolated “general-purpose interface” (GPI) ports available at the REMOTE INTERFACE connector.The 5518 is the ideal choice for network broadcasters who process with an FM audio processor at the network origination point.It is also useful when the connection to the studio is through an STL using lossy compression that introduces overshoots.Using phase-linear filters, the 5518 can precisely control the audio bandwidth to 15, 16 or 17 kHz, user-selectable.You can select the bandwidth to prevent overshoots in uncompressed digital links operating at 32 or 44.1 kHz sample rate.All bandwidths protect the pilot tone and RDS (or RBDS) subcarrier(s) from interference.


-Frequency Response (Bypass Mode):Follows standard 50μs or 75μs pre-emphasis curve ±0.10 dB, 2.0 Hz–15 kHz. Analog left/right output and digital output can be user- configured for flat or pre-emphasized output.
-Noise: <–85 dB below 100% modulation, 30-15,000 Hz, deemphasized.
-Total System Distortion (de-emphasized, 100% modulation): <0.01% THD, 20 Hz–1 kHz, rising to <0.05% at 15 kHz. <0.02% SMPTE IM Distortion.
-Total System L/R Channel Separation: >55 dB, 20 Hz – 15 kHz; 60 dB typical.
-Polarity (Two-Band and Bypass Modes): Absolute polarity maintained. Positive-going signal on input will result in positive-going signal on output.
-Processing Sample Rate: The 5518 is a “multirate” system, using internal rates from 64 kHz to 512 kHz as appropriate for the processing being performed. L/R overshoot limiters operate at 256 kHz (and are anti-aliased), while the composite limiter operates at 512 kHz.
-Processing Resolution: Internal processing has 24 bit (fixed point) or higher resolution.