Cisco Cisco Prisma II EDR Receiver Data Sheet
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Data Sheet
Features
Blind-mate (push-on) connections for RF, power, and data
RF test points (one for each independent optical receiver)
Adjustable RF output levels
Optical automatic gain control
Multiple setup and control options
Local control via Local Craft Interface (LCI) and / or Intelligent Communications Interface
Module (ICIM)
Remote monitoring via ROSA / TNCS
Master / Slave or Independent Mode Redundancy
Calculating Reverse Receiver RF Output Level
Use the appropriate full link gain formula below together with the following procedures to
determine receiver (Rx) RF output level for design purposes.
Use the appropriate full link gain formula below together with the following procedures to
determine receiver (Rx) RF output level for design purposes.
Receiver Type
Full Link Gain Formula
High Density Dual Low Noise Reverse Optical Receiver
84 - mpeak + (2 x Pin)
HD-RXR - High Gain or Low Noise
84 - mpeak + (2 x Pin)
1. Calculate the full link gain using the appropriate formula above, where:
◦
mpeak
is the reverse transmitter single CW carrier RF input (drive) level, expressed
in dBmV, that produces 100% peak OMI.
◦
Pin
is the reverse receiver optical input power, expressed in dBm.
The resulting full link gain is the gain of the link in dB from the reverse transmitter RF
input to the reverse receiver RF output, with receiver output attenuation set to minimum (0
dB).
input to the reverse receiver RF output, with receiver output attenuation set to minimum (0
dB).
2. Calculate the usable link gain as follows:
a. Add the full link gain to the reverse transmitter maximum expected composite RF
input (drive) level to determine the maximum expected Rx composite RF output level.
b. Determine if the maximum expected reverse Rx composite RF output level exceeds
the maximum RF output level specification.
If it exceeds the maximum, calculate the amount of Rx RF attenuation (level
If it exceeds the maximum, calculate the amount of Rx RF attenuation (level
reduction in dB) required to prevent such occurrence. Then calculate the usable link
gain using the formula:
Usable Link Gain = Full Link Gain - Rx Attenuation
If it does not exceed the maximum, then the full link gain is equal to the usable link
Usable Link Gain = Full Link Gain - Rx Attenuation
If it does not exceed the maximum, then the full link gain is equal to the usable link
gain (no Rx attenuation required).
3. Calculate the receiver RF output level as follows:
◦
Rx RF Output Level = Tx Design RF Input Level + Usable Link Gain
This formula yields the RF output level that can be used for reverse RF design in the headend or
hub site where the receiver is located.
hub site where the receiver is located.
Note
:
Many systems are designed for a common Rx RF output level by first calculating output level for
the link(s) with greatest optical loss. For links with lower optical loss, Rx RF attenuation is then
added (2 dB for each dB lower optical link loss) to achieve the common Rx RF output level.
the link(s) with greatest optical loss. For links with lower optical loss, Rx RF attenuation is then
added (2 dB for each dB lower optical link loss) to achieve the common Rx RF output level.