Olson Technology OTPN-800CH - Manual (Page 5)

Table 1 - Setup Reference
Although the node will operate at optical input levels as high as +2dBm, there is little
improvement in the CNR performance of the node at optical input levels above 0 dBm.
For optimum distortion performance, it is recommended that the optical input to the
node be kept at or below 0 dBm. The Olson Technology Model OTOA-1000 optical
attenuator is ideal for this application. To lower the output level the adjustable pad
should be increased but a reduction below +38dBmV output at 547.25 MHz by this
method is not recommended. If lower output is desired, the unit should be set for
+35dBmV and an in-line pad added to the RF output to reduce the output level. This will
maintain optimum CNR performance. This will also reduce the OMI of the return
transmitter if so equipped.
Unlike many optical nodes, the OTPN-800CH is designed to give full output perfor-
mance at an input of -8 dBm. Figure 1 shows the approximate CNR performance at
various input levels and channel loading. This performance can vary considerably
depending upon fiber and laser performance so it is presented as a design aid only.
The OTPN-800CH ships with an 10dB forward equalizer which gives 6dB of slope from
54-1,000 MHz. This can be changed by the user to vary the amount of slope that the unit
has. A higher value equalizer will give more slope, while a lower value equalizer will give
less slope. This is so that the unit can be properly setup for the amount of coax that the
output will be going through. Longer distances require more slope then shorter
distances.