Optimod-FM 8600S: Specifications

It is impossible to characterize the listening quality of even the simplest limiter or compressor based on specifications because such specifications cannot adequately describe the crucial dynamic processes that occur under program conditions. Therefore, the only way to evaluate the sound of an audio processor meaningfully is by subjective listening tests.

Certain specifications are presented here to assure the engineer that they are reasonable, to help plan the installation, and make certain comparisons with other processing equipment.

Performance

Except as noted in the text, specifications apply for measurements from analog left/right input to stereo composite output and to FM analog left/right output.
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: Output noise floor will depend upon how much gain the processor is set for (Limit Drive, AGC Drive, Two-Band Drive, and/or Multi-Band Drive), gating level, equalization, noise reduction, etc. The dynamic range of the A/D Converter, which has a specified overload-to–noise ratio of 110 dB, primarily governs it. The dynamic range of the digital signal processing is 144 dB.
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: >50 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 when HD Polarity and FM polarity controls are set to Positive.
Processing Sample Rate: The 8600S is a “multirate” system, using internal rates from 64 kHz to 512 kHz as appropriate for the processing being performed. Audio clippers operate at 256 kHz (and are anti-aliased), while the composite limiter operates at 512 kHz.
Peak Control at HD Output: The peak limiter is oversampled at 256 kHz, yielding a worst-case overshoot of 0.4 dB at the analog output and for all output sample rates. (To achieve this performance at 32 kHz output sample rate, it is necessary to set the 8600S’s HD lowpass filter cutoff frequency to 15 kHz.)
Processing Resolution: Internal processing has 24 bit (fixed point) or higher resolution.

Installation

Delay

Defeatable Analog FM Processing delay: 0.27 to 16.384 seconds, adjustable in one-sample increments at 64 kHz sample rate to allow the delays of the analog and digital paths in the HD Radio system to be matched at the receiver output.
Minimum Processing Delay: Processing structure dependent. Typically 17 ms for normal latency Five-band, 13 ms for low-latency Five-band, 3.7 ms for ultra-low-latency Five-band, and 17 or 22 ms for 2-band, depending on crossover structure chosen. MX presets have approximately 270 ms delay.

Analog Audio Input

Configuration: Stereo.
Impedance: >10kΩ load impedance, electronically balanced.
Nominal Input Level: Software adjustable from –9.0 to +13.0 dBu (VU).
Maximum Input Level: +27 dBu.
Connectors: Two XLR-type, female, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
A/D Conversion: 24 bit 128x oversampled delta sigma converter with linear-phase anti-aliasing filter.
Filtering: RFI filtered, with high-pass filter at 0.15 Hz.

Analog Audio Output

Configuration: Stereo. Flat or pre-emphasized (at 50µs or 75µs), software-selectable.
Source Impedance: 50Ω, electronically balanced and floating.
Load Impedance: 600Ω or greater, balanced or unbalanced. Termination not required or recommended.
Output Level (100% peak modulation): Adjustable from –6 dBu to +24 dBu peak, into 600Ω or greater load, software-adjustable.
Signal-to-Noise: >= 90 dB unweighted (Bypass mode, de-emphasized, 20 Hz–15 kHz bandwidth, referenced to 100% modulation).
L/R Crosstalk: <= –70 dB, 20 Hz–15 kHz.
Distortion: <= 0.01% THD (Bypass mode, de-emphasized) 20 Hz–15 kHz bandwidth.
Connectors: Two XLR-type, male, EMI-suppressed. Pin 1 chassis ground, Pins 2 (+) and 3 electronically balanced, floating and symmetrical.
D/A Conversion: 24 bit 128x oversampled, with high-pass filter at 0.15 Hz (–3 dB).
Filtering: RFI filtered.

Digital Audio Input

Configuration: Stereo per AES3 standard, 24 bit resolution, software selection of stereo, mono from left, mono from right or mono from sum.
Sampling Rate: 32, 44.1, 48, 88.2, or 96 kHz, automatically selected.
Connector: XLR-type, female, EMI-suppressed. Pin 1 chassis ground, pins 2 and 3 transformer balanced and floating, 110Ω impedance.
Input Reference Level: Variable within the range of –30 dBFS to –10 dBFS.
J.17 De-emphasis: Software-selectable.
Filtering: RFI filtered.

Digital Audio Outputs

Configuration: Two outputs, each stereo per the AES3 standard. The outputs can be independently set to emit the analog FM processed signal, the digital radio processed signal, or the low-delay monitor signal. The FM processed signal can be configured in software as flat or pre-emphasized to the chosen processing pre-emphasis (50µs or 75µs). The digital radio processing chain receives the output of the multiband limiter and processes it through a look-ahead peak limiter that operates in parallel with the main FM peak limiting system. The DR and FM signals are always simultaneously available. Each output can apply J.17 pre-emphasis if desired.
Sample Rate: Internal free running at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, or 96 kHz, selected in software. (Use 44.1 kHz or higher for best peak control.) Can also be synced to the AES3 SYNC input or the AES3 digital input at 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz, as configured in software.
Word Length: Software selected for 24, 20, 18, 16 or 14-bit resolution. First-order highpass noise-shaped dither can be optionally added, dither level automatically adjusted appropriately for the word length.
Connector: XLR-type, male, EMI-suppressed. Pin 1 chassis ground, pins 2 and 3 transformer balanced and floating, 110Ω impedance.
Output Level (100% peak modulation): –20.0 to 0.0 dBFS software controlled.
Filtering: RFI filtered.
Frequency Response (Digital Audio Output (from Digital Radio Processing Chain)): For output sample rates of 44.1 kHz and above, the frequency response from input to DR-configured output is ±0.10 dB, 2.0 Hz - 20 kHz; flat or with J.17 pre-emphasis applied. The user may specify lowpass filtering to constrain the bandwidth to 15, 16, 17, 18, or 19 kHz.
Relative Time Delay between FM and HD Outputs: Depends on setting of analog processing channel diversity delay. Once set, this delay is constant regardless of processing preset in use.

Wordclock/10 MHz Sync Reference

Configuration: Accepts 1x wordclock or 10 MHz reference signals, automatically selected. The DSP master clock can be phase-locked to these signals, which in turn phase-locks the 19 kHz pilot tone frequency, facilitating singe-frequency network operation. The digital output sample frequency can also be locked to these signals.
Level: Unit will lock to 1x wordclock and 10 MHz squarewaves and sinewaves having a peak value of 0.5 V to 5.0 V.
Connector: BNC female, grounded to chassis, non-terminating to allow reference signals to be looped through via an external BNC “tee” connector (not supplied).

AES3id Input

Configuration:The Wordclock/10 MHz Sync Reference can also be configured as an AES3id digital audio input to drive the input of the stereo encoder. This facilitates a “ratings encoder loop-through” connection, where the input of the ratings encoder is driven from one of the 8600S’s AES3 outputs and the encoder’s output is returned to the AESid input. When not being used in ratings encoder loop-through mode, this input can receive an AES3id or AES11id sample rate reference signal to which the 8600S’s digital outputs can be locked.
Connector: BNC female, grounded to chassis, terminated with 75Ω. For short cable runs, there is usually no problem in driving this with an AES3 (110Ω) signal. If the cable is long enough to cause digital audio reception errors due to impedance mismatch, a 110Ω/75Ω transformer should be placed in-line.

Composite Baseband Outputs

Configuration: Two outputs, each with an independent software-controlled output level control, output amplifier and connector.
Source Impedance: 0Ω voltage source or 75Ω, jumper-selectable.
Load Impedance: 37Ω or greater. Termination not required or recommended.
Maximum Output Level: +16.0 dBu (13.82Vp-p).
Pilot Level: Adjustable from 6.0% to 12.0%, software controlled.
Pilot Stability: 19 kHz, ±1.0 Hz (10 degrees to 40 degrees C).
D/A Conversion: 24-bit
Signal-to-Noise Ratio: >= 85 dB (Bypass mode, de-emphasized, 20 Hz – 15 kHz bandwidth, referenced to 100% modulation, unweighted).
Distortion: <= 0.02% THD (Bypass mode, de-emphasized, 20 Hz – 15 kHz bandwidth, referenced to 100% modulation, unweighted).
Stereo Separation: >50 dB, 20 Hz – 15 kHz; 60 dB typical.
Crosstalk-Linear: <= –80 dB, main channel to sub-channel or sub-channel to main channel (referenced to 100% modulation).
Crosstalk-Non-Linear: <= –80 dB, main channel to sub-channel or sub-channel to main channel (referenced to 100% modulation).
38 kHz Suppression: >= 70 dB (referenced to 100% modulation).
76 kHz & Sideband Suppression: >= 80 dB (referenced to 100% modulation).
Pilot Protection: 60 dB relative to 9% pilot injection, ±250 Hz (up to 2 dB composite processing drive).
Subcarrier Protection (60-100 kHz): >= 70 dB (referenced to 100% modulation; with up to 2 dB composite limiting drive; measured with 800 line FFT analyzer using “maximum peak hold” display).
57 kHz (RDS/RBDS) Protection: 50 dB relative to 4% subcarrier injection, ±2.0 kHz (up to 2 dB composite processing drive).
Connectors: Two BNC, shell connected to chassis ground, EMI suppressed.
Maximum Load Capacitance: 0.047 microfarad (0Ω source impedance). Maximum cable length of 100 feet/30 meters RG–58A/U.
Filtering: RFI filtered.

Subcarrier (SCA) Inputs

Configuration: Two subcarrier inputs sum directly into composite baseband outputs; COMPx LVL control settings have no effect on the absolute subcarrier levels.
Impedance: 600Ω
SCA Sensitivity: Variable from <100 mV p-p to >10 V p-p to produce 10% injection assuming 100% modulation = 4 V p-p at the 8600S’s composite outputs. Rear-panel accessible PC-board-mounted trim pots allow user to adjust the sensitivities of the two SCA inputs.
Connectors: Two BNC, shell connected to chassis ground, EMI suppressed.
19 kHz Pilot Reference: SCA2 input can be re-jumpered to provide a 19 kHz pilot reference output.

Remote Computer Interface

Supported Computer and Operating System: IBM-compatible PC running Microsoft Windows^® XP or higher.
Configuration:TCP/IP protocol via direct cable connect, modem, or Ethernet interface.
Serial Connector: RS–232 on DB–9 male connector, EMI-suppressed. Uses PPP to provide for direct or modem connection to the 8600S PC Remote application.
Ethernet Connector:Female RJ45 connector for 10 Mbps and higher networks using CAT5 cabling. Native rate is 100 Mbps. Provides for connection to the 8600S PC Remote application through either a network, or, using a crossover Ethernet cable, directly to a computer.
Ethernet Networking Standard: TCP/IP.

Remote Control (GPI) Interface

Configuration: Eight (8) inputs, opto-isolated and floating.
Voltage: 6–15V AC or DC, momentary or continuous. +12VDC 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, stereo or mono modes, analog input, digital input.
Filtering: RFI filtered.

Tally Outputs

Circuit Configuration: Two NPN open-collector outputs.
Voltage: +15 volts maximum. Do not apply negative voltage. When driving a relay or other inductive load, connect a diode in reverse polarity across the relay coil to protect the driver transistors from reverse voltage caused by inductive kickback.
Current: 30 mA maximum
Indications: Tally outputs can be programmed to indicate a number of different operational and fault conditions, including Input: Analog, Input: Digital, Analog Input Silent, AES Input Silent, and AES Input Error.

Power

Voltage: 85–264 VAC, 50–60 Hz, <30 VA.
Connector: IEC, EMI-suppressed. Detachable 3-wire power cord supplied.
Fuse: 2.5A 20mm Quick Acting HBC, mounted on the power supply circuit board.
Grounding: In order to meet EMI standards, circuit ground is hard-wired to chassis ground.
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.
Dimensions (W x H x D): 19” x 1.75” x 14.25” / 48.3 cm x 4.5 cm x 36.2 cm. One rack unit high.
Humidity: 0–95% RH, non-condensing.
RFI/EMI: Tested according to Cenelec procedures. FCC Part 15 Class A device.
Shipping Weight: 10 lbs / 4.6 kg

Warranty

Five Years, Parts and Service: Subject to the limitations set forth in Orban's Standard Warranty Agreement.

Because engineering improvements are ongoing, specifications are subject to change without notice.

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¹No jumper selection available for 600Ω. Surface-mount pads are available on I/O module for user-installed 600Ω termination.