2 – Functional Design
HD Link Installation & Operation Manual
Version 2, April 2010
Harris Corporation
2-7
Intraplex Products
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A transmitter and receiver with 200, 250, 300, 375, or 500 kHz of RF bandwidth.
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LDPC advanced error correction – requires less receive signal than Reed-Solomon to achieve an
equivalent BER, a critical parameter for glitch-free HD Radio performance.
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State-of-the-art modulation technology operating at 32, 64, 128, or 256 QAM that can provide
more than 3 Mbps throughput.
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Built-in circulator so that an HD Link unit can withstand infinite VSWR at up to 25 W of power.
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High sensitivity and selectivity RF receiver circuits.
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As much as 10 dB overall system gain improvement over older digital STLs.
2.3.4
Setup & Operation
These features provide easy setup and reliable operation:
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Advanced Web browser user interface and SNMP remote control
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Front-panel Ethernet port to access the Web browser interface and diagnostics
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USB port to save configurations and update software
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FTP access for remote software uploads
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User-configurable control input and alarm output contacts
2.3.5
Connectors & Display
The HD Link system also offers these convenient connections and display:
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XLR AES/EBU digital and L/R analog input/output connectors
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Headphone jack on receiver for audio monitoring
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AES/EBU sync port on the receiver
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Analog level outputs for forward power and reflected power (on transmitter unit) and for received
signal level and signal-to-noise (on receive unit)
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Intuitive front panel interface display with liquid crystal display (LCD) levels for all audio programs
at each end
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Optional main/alternate interface for redundancy switching
2.4 New Features – Software Release 2.0
Release 2.0 of the HD Link system includes these features:
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G.722 audio transport encoding/decoding
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In-band messaging and synchronization between transmitter and receiver
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Transmitter-receiver redundancy (using two transmitters and two receivers)
2.4.1
Audio Transport Using G.722 Coding
The ITU-T G.722 audio coding standard defines a method for encoding/decoding 7 kHz audio into 64
kbps. G.722 coding uses a form of sub-band adaptive differential pulse code modulation (SB-ADPCM)
audio compression.
The HD Link transmitter and receiver now provide two mono channels of G.722 encoding/decoding to
transport audio analog, offering these audio performance capabilities:
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14 bit sample size
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16 ksps sample rate
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64 kbps data rate per channel
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50 to 7000 Hz, ±1 dB audio frequency response
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Dynamic range greater than 65 dB