Enhanced Digital Return System Overview
Features
The EDR Enhanced Digital Return 1:1 and 2:1 Multiplexing Systems have the following features.
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High-performance Digital Return technology
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12 bit encoding enables transmission of analog video in the reverse band
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High-order digital modulation signals (e.g.,16 QAM, 64 QAM, and 256 QAM)
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Multiple operating modes in the EDR receiver support EDR transmitter
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Optical Pluggable Modules (OPM) enable flexible inventory management
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Long reach transmission capabilities eliminate the need for optical amplifiers, reducing cost and space requirements
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Capable of sending 80 individual 5 – 85 MHz reverse signals over a single fiber
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Compatible with Cisco’s 40 wavelength DWDM system
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Enables independent balancing of reverse traffic at EDR receiver RF ports
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Simplified setup reduces installation time and expertise requirements
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Distance- and temperature-independent link performance simplifies engineering and maintenance requirements
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Space-saving, high-density deployment in Prisma II or Prisma II XD chassis increases deployment cost-efficiency
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Optional monitoring of node (GS7000) and Tx (GS7000 and GainMaker) parameters available at the receiver
The EDR 2:1 Enhanced Digital Return Multiplexing System leverages 2:1 multiplexing to reduce fiber usage.
System Functional Diagram
The following illustration shows how the GS7000 Node functions in Enhanced Digital Return configuration with 1:1 EDR transmitter module installed as the transmitter.
 Note |
When the node is configured in either segmented or EDR mode, a 75 dB pad must be placed in the Tx2 SM Term. |
Important |
This configuration requires a 4x1 Reverse Configuration Module (for 6-port OIB), as shown. |
EDR Transmitter Module
At the transmit (node) end of the system, reverse-path RF input signals from each node port are routed to an EDR 2:1 or EDR 1:1 Transmitter module in the housing lid. The transmitter module converts each signal to a baseband digital data stream and combines the signals into a serial data stream using time-division multiplexing (TDM). The baseband data stream is then converted to an optical signal for transmission to the headend or hub. The double-wide (2:1) transmitter modules occupy two transmitter slots and the 1:1 modules occupy one slot.
The EDR 1:1 transmitter introduces one single RF inputs to produce the discrete 5 to 85 MHz RF signal, while the EDR 2:1 transmitter introduces two RF inputs to produce two discrete 5 to 85 MHz RF signals. The transmitter module also converts each signal to a baseband digital data stream and time division multiplexes the two streams into a single data stream.
The data stream is carried optically over fiber, via an SFP type OPM module, to a remote hub or headend location where the optical signal is detected and converted back to a serial electrical signal. The data is then de-scrambled and de-framed and switched to a Digital-to-Analog Converter (DAC), where the analog spectrum that was sampled at the transmit side is reconstructed. The baseband data stream is converted to an optical signal for transmission back to the headend or hub.
The following block diagrams show the transmitter module's internal components.
The following illustrations show the transmitter module components.
Note |
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The transmitter module uses the same style housing as the optical receivers and transmitters, and it uses the single-wide module housing. As such, it occupies one standard transmitter positions in the node lid.
Note |
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The transmitter module uses the same style housing as the optical receivers and transmitters, except that it uses double-wide module housing. As such, it occupies two standard transmitter positions in the node lid.
EDR Receiver Module
At the receive end, typically in a large hub or headend, the EDR Receiver module receives the optical signal and performs the conversion back to the baseband data stream. The resulting data streams are converted back to analog reverse path signals for routing to termination equipment. The EDR Receiver module is available in the High Density form factor. The receiver OPMs are available in Standard Range (SR) and Extended Range (XR) configurations. Both configurations feature a dual LC/PC optical input connector that feeds two independent reverse optical receivers, each with its own RF output port.
A single EDR Receiver module occupies one slot in a Cisco Prisma II XD chassis. Two EDR HD receiver modules can be vertically stacked in an associated Prisma II Host Module that occupies a single-wide slot in the Prisma II standard chassis. Up to 26 HD modules can operate in a standard 6 rack unit (6RU) chassis (the 56-connector version of the chassis is required to make use of both receivers in one chassis slot). Up to 16 HD modules can operate in the Prisma II XD chassis. The ability to mix EDR Receiver modules with other Prisma II HD modules in the same chassis greatly enhances the flexibility of the platform.
For instructions on installing the receiver, refer to the Prisma II Chassis Installation and Operation Guide.
The following illustration shows the receiver module.
The following block diagram shows the receiver module's internal components.
At the headend, the reverse optical receiver converts the optical signal back to an RF signal that is then routed out through the receiver's RF output.
For detailed information on the EDR receiver module, refer to the Cisco Prisma II EDR Receiver Installation Guide.
Receiver Operating Modes
The receiver module supports receiver mode configuration performed by setting the proper mode ID numbers in the Prisma II Web UI system.
The following diagrams provide a basic walk-through of all the supported modes for the EDR receiver module.
The receiver can be configured for any of the following modes of operation:
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Single 2:1
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Dual 1:1
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Dual 2:1
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Single 2:1 on Primary + Single 1:1 on Secondary
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Single 1:1 on Primary + Single 2:1 on Secondary
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Legacy Single 2:1
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Legacy Dual 2:1
Single 2:1 Mode
Referring to the diagram below, the EDR transmitter digitizes and combines two RF signals (RF 1 + RF 2) into one serial stream and transmits is over optical fiber to the receiver. At the receiver, the serial stream is de-serialized, converted back to its two analog RF components, and then sent to the two RF connectors on the back of the module. RF 1 appears on RF port A, and RF 2 appears on RF port B.
Note |
The optical fiber must be plugged into the top receiver on the OPM. |
Dual 1:1 Mode
Referring to the diagram below, the EDR transmitter digitizes a single RF signal (RF 1) into a serial stream and transmits it over optical fiber to the receiver. At the receiver, the serial streams from two separate transmitters are deserialized and converted back to an analog RF signal. The RF signal (RF 1) for each transmitter is sent separately to the two RF connectors on the back of the module.
Dual 2:1 Mode
Referring to the diagram below, two EDR transmitters are connected to one receiver. Each EDR transmitter digitizes and combines two RF signals (RF 1 + RF 2) into one serial stream and transmits it over optical fiber to the receiver. At the receiver, the serial streams from the two separate transmitters are deserialized and converted back to their two analog RF components. Since the receiver only has two RF ports, the combined signals (RF 1 + RF 2) for each transmitter are sent to the two RF connectors on the back of the module.
Single 2:1 on Primary + Single 1:1 on Secondary
This mode is a combination of the 2:1 and 1:1 modes described above. Referring to the diagram below, one EDR transmitter digitizes and combines two RF signals (RF 1 + RF 2) into one serial stream and transmits it over optical fiber to the receiver. The other EDR transmitter digitizes a single RF signal (RF 1). At the receiver, the serial streams from two separate transmitters are deserialized and converted back to their two analog RF components. The combined Transmitter 1 signal (RF 1 + RF 2) is sent to RF port A, and the Transmitter 2 signal (RF 1) is sent to RF port B on the back of the module.
Single 1:1 on Primary + Single 2:1 on Secondary
This mode is identical to the mode just described, except that the 2:1 transmitter is connected to the second receiver and the 1:1 transmitter is connected to the primary receiver.
EDR OPM and LCM
The reverse transmitter converts the RF test signal(s) to an optical signal using the installed Optical Module (OPM) and transmits it to the headend (or hub site) via fiber optic cable. At the headend, the reverse optical receiver also converts the optical signal back to an RF signal that is then routed out through the receiver's RF output using its installed OPM module.
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1 |
Dust Plug |
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2 |
Bale Clasp (Open, Push upward to close) |
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3 |
Transmit Bore (Not In Use for the Receiver) |
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4 |
Receive Bore (Not In Use for the Transmitter) |
The EDR Local Control Module is required for in-band status monitoring the node signaling and data transmission.
The packet cable is delivered with the EDR LCM module. Refer to the installation section in the following content for instructions on local status monitoring connection.
Refer to the following sections for EDR OPM and LCM installation.
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