Orban OPTIMOD-FM 8700, Operating Manual

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6-2
TECHNICAL DATA ORBAN MODEL 8700i
Installation
Delay
Defeatable Analog FM Processing delay: 0.27 to 12.0 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. To avoid introducing artifacts
in the analog FM path, its delay is held constant and HD delay is varied if the adjustment
does not exceed ±1.3 seconds. Larger adjustments change the analog FM delay and re-
center the HD delay within the ±1.3 second window.
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 pre-
sets have approximately 270 ms delay. The multipath mitigator adds 146 ms of addition-
al delay, and can be bypassed in situations like outside broadcasts where talent needs
to monitor off-air. The subharmonic synthesizer adds 67.5 ms of delay and can be by-
passed. To achieve these delays, the diversity delay must be defeated on all outputs:
analog, digital, IP, and composite; otherwise, the delay will be 1.3 seconds longer.
Headphone Monitor Processor Delay : The low-delay, dedicated headphone monitor pro-
cessor has 5 ms of delay and provides a complete FM processing chain, including 5-
band compressor and distortion-cancelled FM clipper. The clipper drive is adjustable to
allow dialing in the preferred amount of “FM clipper sound.”
Analog Audio Input
Configuration: Stereo.
Impedance: > 10k

load impedance, electronically balanced
1
.
Nominal Input Level: Software adjustable from
–4.0 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.
Hardwire Bypass: Removing power from the Optimod will connect the left and right
audio inputs to the left and right audio outputs via a relay.
Analog Audio Output
Configuration: Stereo. The analog output can emit the analog FM processed signal, the
digital radio processed signal, or the low-delay monitor signal. The FM processed signal
can be flat or pre-emphasized (at 50
µ s or 75 µ s), software-selectable.
Source Impedance: 50

, electronically balanced and floating.
Load Impedance: 600

or greater, balanced or unbalanced. Termination not required, or
recommended.
Output Level (100% peak modulation): Adjustable from
–6 dBu to +24 dBu peak, into 600

or greater load, software-adjustable.
1
No jumper selection available for 600

. Through-hole pads are available on I/O
module for user-installed 600

termination.