Customers always ask if OAU boards can still meet the requirement of getting the same Channel Gain after connected to DCM or not.
First, make sure Input Power of DCM must be less than -3dBm and then the following formula must be
(1) Channel gain (dB) = Pout (dBm) - Pin (dBm)
(2)Channel gain (dB) + Insertion loss of DCM (dB) ≤ Max. total gain (dB) - 2dB (VOA)
Note:OAU1 is a two-stage-amplifier and DCM can be connected between two stages. And there is a built-in VOA in OAU1, its insertion loss (2dB) should be considered.
For example, DCM(C) - for G.652 - 60km (insertion loss is 5.8dB) is connected to OAU101, 26dB
Channel Gain is required. This value are put into formula: Channel gain (dB) + Insertion loss of DCM
(dB) ≤ Max. total gain (dB) - 2dB (VOA), that is 26+5.8≤33-2. OAU101 cannot meet the requirement, even
though its gain range is from 20dB to 31dB. If OAU103 is used, the same Channel Gain is required, and
DCM is the same. Similarly, Channel gain (dB) + Insertion loss of DCM (dB) ≤ Max. total gain (dB) - 2dB
(VOA), that is 26+5.8≤38-2. OAU103 can be working. The specification of different OA ( for 40 channel )
are listed as follows:
The Channel Gain of OAU is not only related with its gain range but also the Insertion loss of DCM and Maximum