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Optimod-DAB 6200

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Overview

Audio Processor for Digital Television Broadcasting

OPTIMOD-DAB 6200 is the first audio processor designed specifically forthe requirements of digital television (DTV) transmission. The 6200's transparent protection limiter controls peaks for absolute protection from digital clipping, but without adding low-level spectral "trash" that can stress the perceptual codecs. The 6200 also provides both two-band and five-band OPTIMOD processing structures to ensure source-to-source consistency and tailor your sound for maximum impact. The 6200 is compatible with all digital television applications, including terrestrial, cable or satellite distribution of mono, two-channel or Dolby Surround encoded program.

Features

*This processor does not accommodate 5.1 channel audio, but can be used for standard stereo and Dolby Stereo matrix surround material.

Specifications

SYSTEM

Frequency Response: ±0.1dB, 2-20,000Hz (Bypass mode).
Input/Output Delay: Approximately 15 milliseconds. Can be padded to full frame of: 24 milliseconds, 30 fps (33.33ms), 29.97 fps (NTSC color video; 33.37ms), 25 fps (most PAL video; 40ms), 24 fps (film; 41.67ms), and 96 milliseconds.
Internal Filters: (4.0 to 11.5kHz in 500Hz steps), 12, 13, 14, 15, 20kHz provide anti-aliasing for low sample rate services, such as Eureka-147 (24kHz mode), and the proposed AM IBOC (32kHz) and shortwave IBOC systems.
Internal Sample Rate: 48kHz.
Internal Resolution: 24-bit fixed point (Motorola DSP56009).
Input/Output Resolution: 20-bit, limited by Analog Devices sample rate converters.
Peak Control Accuracy: If output samples are synchronous with internal samples, maximum overshoot of any output sample is 0.1dB. This is true at 48kHz output sample rate. If sample rate conversion after internal processing makes output samples asynchronous with internal samples, output samples can overshoot as much as 1dB (0.3dB typical).
Phase Response: All processing is linear-phase (constant group delay).
Internal Processing: Input -> Two-Band defeatable AGC -> Four-Band Equalizer -> Multiband Compressor -> Look-ahead Limiter -> Output.
Multiband Compressors: Three available: Five-Band, Two-Band, and Protect, selectable by mute-free crossfade.
Equalizers: Shelving Low Bass Eq, selectable 12dB or 18dB/octave Shelving Mid Bass Eq. Parametric Midrange Eq with analog-style bell-shaped curves.
Parametric High Frequency Eq with analog-style bell-shaped curves.
Number of Factory Presets: 26, each with 19-step LESS-MORE control. Presets are fully customizable with FULL CONTROL.
Number of User Presets: 32 memory locations to save customized presets.

ANALOG AUDIO INPUT

Configuration: Stereo.
Impedance: Electronically balanced 600 ohms or <10k ohms impedance, selected using a configuration jumper.
Nominal Input Level: Software adjustable (via AI REF control) -9 dBu to +13 dBu VU (-1 dbu to +21 dBu PPM).
Maximum Input Level: +27 dBu, peak.
Connector: Two XLR-type, female, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
AD Conversion: 24-bit 128X oversampled delta sigma A/D converter with linear phase anti-aliasing filter.
RF Filtering: Effective 0.5-1000MHz.
High Pass Filter: 0.15Hz.

ANALOG AUDIO OUTPUT(MONITOR)

Note that this output is not intended to be used as a transmitter output, rather it is for monitoring. Nevertheless it has been designed for low noise, distortion, and overshoot and can drive an STL or transmitter in an analog plant. Peak control will not be as good as at the digital output because on-air samples will be asynchronous with peak-controlled internal samples. The source of this output is switchable between the peak limiter output and the multiband compressor output. Because most of the delay occurs in the peak limiter, this can make headphone monitoring much more comfortable for on-air talent.

Configuration: Stereo.
Source Impedance: 30 ohms, electronically balanced and floating.
Load Impedance: 600 ohms or greater, balanced or unbalanced. Termination not required or recommended.
Output Level: Fixed at +14 dBu peak, with MON OUT source set to "POST LIMiter." Pre-limiter peaks up to +26 dBu possible. No output level adjustment control provided.
Signal-to-Noise: 90 dB unweighted signal-to-noise, 20Hz-20kHz (bypass mode).
Distortion: £0.01% THD (bypass mode), 20Hz-20kHz.
Connector: Two XLR-type, male, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
DA Conversion: 20-bit 128X oversampled D/A converter.
DC Offset: Less than 10mV.
Filtering: RFI filtered. Effective 0.5-1000MHz.

DIGITAL AUDIO INPUT

Configuration: Stereo per AES/EBU-standard (AES3-1992), 20-bits resolution, software selection of stereo, mono from left, mono from right, or mono from sum (as source to use as a mono processor).
Sampling Rate: 32, 44.1 and 48kHz.
Connector: XLR-type, female, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 transformer balanced and floating, 110 ohms impedance.
Status Bits: Input channel status is ignored. Input User bits are optionally passed through to the output.
Input Reference Level: Variable within the range of -30 to -10dBFS (VU) in 0.5dB steps.
Filtering: RFI filtered. Effective 0.5-1000MHz.

DIGITAL AUDIO OUTPUT

Configuration: Two-channel per AES/EBU-standard (AES3-1992).
Output Level Control: Peak level is adjustable from -20dBFS to 0 in 0.1dB steps. Controlled by software.
Sampling Rate: Internal free running at 32kHz ±10 PPM, 44.1kHz ±100 PPM, or 48kHz ±10 PPM, selected in software. Can also be synced to the AES/EBU SYNC input or the AES/EBU DIGITAL input at 32kHz ± 4%, 44.1kHz ± 4%, or 48kHz ± 4%.
Word Length: Selectable 20, 18, or 16 bit. Optional dither can be added, with level adjusted appropriate to word length. This is first-order noise-shaped dither. (i.e., white TPDF dither of peak amplitude equal to the quantizer step size with noise shaping spectral density of 6dB/octave.) It sounds substantially quieter than white triangular PDF dither but, in contrast to more extreme noise-shaped dither, it adds only 3dB unweighted noise by comparison to white PDF dither.
Sync: Internal free running or external per AES11. The "AES/EBU SYNC Input" is the primary source for external sync. The "AES/EBU Input" is an alternate source.
Connector: XLR-type, male, EMI-suppressed. Pin 1 chassis ground, Pins 2 and 3 transformer balanced and floating.
Status/User Bits: The channel status optionally supports the S/PDIF or AES/EBU formats. The user bits received from the "AES/EBU input" are optionally passed through to the output. The 192-bit block structure is used where prea ble "Z" indicates the start of block.
Jitter: Less than 10ns rms.
Filtering: RFI filtered. Effective 0.5-1000MHz.

DIGITAL SYNC INPUT

Configuration: Used for synchronization of the Digital Output signal to an external reference provided at this input. Labeled "AES/EBU Sync Input."
Sampling Rate: 32, 44.1 and 48kHz.
Connector: XLR-type, female, EMI-suppressed. Pin 1 chassis ground, Pins 2 and 3 transformer balanced and floating, 110W impedance.
Filtering: RFI filtered.

REMOTE CONTROL INTERFACE

Configuration: Eight (8) inputs, opto-isolated and floating, and two open-collector fault tally outputs.
Voltage: 6-24V AC or DC, momentary or continuous. 9 VDC provided to facilitate use with contact closure.
Connector: DB-25 male, EMI-suppressed.
Control: User-programmable for any eight of user presets, factory presets, bypass, test tone, output sample rate, stereo or mono modes, analog input, digital input, low-pass filter settings, dither on/off, or word lengths.
Tally Outputs: Two tally outputs provided on the Remote Interface Connector, indicating Loss of Digital Signal Lock and Loss of Digital Sync Lock.

POWER

Voltage: 100-132 VAC or 200-264 VAC, switch-selected on the rear panel, 50-60Hz, 50 VA.
Connector: IEC, EMI-suppressed. Detachable 3-wire power cord supplied.
Grounding: Circuit ground is independent of chassis ground; can be isolated or connected with a rear panel switch.
Safety Standards: ETL listed to UL standards, CE marked.

ENVIRONMENTAL

Operating Temperature: 32° to 122° F / 0° to 50° C for all operating voltage ranges.
Humidity: 0-95% RH, non-condensing.
Size: (W x H x D): 19" x 3.5" x 14.25" / 48.3cm x 8.9cm x 36.2cm. Two rack units high.
Weight: 13.5lb/6.1kg.

Notes

Quality TV audio for all viewers and programming.

Let's face it. A few of your viewers are technologically savvy with premier home theater systems located in the ideal listening environment. The rest of your audience? All they want to do is turn on the TV and not worry about adjusting this knob and that one for better audio. Unfortunately, when TV sound reaches them, the potential dynamic range of your broadcast is compromised by background noises such as screaming kids, barking dogs and noisy clothes dryers. At the same time, family members and neighbors who are not watching television don't want to be disturbed by the programs.

Despite all that, both types of viewers want the dialog coming from their TV to be intelligible and the programming levels to be consistent, with no excuses and no loud commercials.

For these challenges, there's OPTIMOD-DAB 6200, the perfect solution for digital terrestrial, cable or satellite origination, for mono, 2-channel and Dolby Surround Encoded programming.

How does the 6200 work with AC-3's DRC?

Dynamic Range Control is only useful for digital TV using Dolby Digital (also known as AC-3) compression under certain circumstances, depending on your programming and audience. Some contemporary TV shows and feature films have been mixed to include DRC and DialNorm which scales the gain before it reaches the volume control on receivers. As a result, these programs can offer full dynamic range in a home theater environment, as well as a comfortable listening range through the average television receiver.

The rest of TV programming rarely needs DRC. News, talk and soap operas are dialog-oriented and don't require wide dynamic range. Instead, dialog intelligibility is the most important technical requirement. Bypassing the "garden variety" programming through the 6200 before broadcast, you automatically achieve source-to-source consistency while preventing commercials from being annoyingly loud.

CBS Loudness Controller tames loud commercials.

Excessively loud commercials are the single most common source of audience complaints about television sound. The 6200's built-in CBS Loudness Controller tames loud commercials. If dialog-oriented programs and commercials are processed through the 6200, your audience, whether they're listening in a home theater environment or on a 19" mono receiver, will receive a quality, consistent sound that doesn't need to be altered. Even if your audience adjusts the DRC control on their receivers, the 6200-processed programming will be consistent and intelligible regardless of their setting.

Choose a single Dolby Digital DialNorm value for all 6200-processed material and the material can be set to match the DRC-encoded programs that are passed on directly to your audience with no processing. By handling most program material automatically, the 6200 will save you time and eliminate operational hassles, while helping you to maintain control over your audio. You'll only have to set individual DialNorm values for programs that can benefit from DRC.

DAB 6200 sound sync options.

The 6200 can be easily incorporated into your DTV plant. It has the ability to pad the throughput delay so that it's exactly one frame of 24, 25 or 29.97-fps video. You can include the 6200 in systems that delay the audio an integer number of frames to maintain lip sync with the picture. There's an AES3 sync input and sample rate converters on the digital inputs and outputs. Consequently, the 6200 can accept synchronous or asynchronous digital inputs at any sample rate between 32 and 48kHz, expanding your capabilities. The AES/EBU output rate can be set to 32, 44.1, 48 and optionally synced to your station's house AES3 sync.