Siemens DataNET Hub (DNH) - Manual (Page 48)

40 •••• Installation 2000585-001
Signal Equalizer Settings for Non Recommended Cable or Unknown
Cable Lengths,
Continued
Step Action
3. Examine the recorded signal levels and determine the dB
loss for each port; refer to Table 2-2.
Example:
With these signal levels, port 4 is the lowest level, so no at-
tenuation is required. Its signal level becomes the reference
for comparing the remaining ports’ signal levels.
The next strongest signal is on port 1. 1.6/1.25 = 1.28
20 log 1.28 = 2.1 dB
or
ratio of 1.28
This is within the 3-dB variance allowed, Use Selection 1 or 0
dB (ratio 1) setting.
The next strongest signal is on port 2. 1.75/1.25 = 1.4
20 log 1.4 = 2.9 dB
or
ratio of 1.4
Since 2.9 dB meets the 3 dB variance allowed, selection 2
can be used (3.5 dB loss), which will put the level at about 0.6
dB below the signal on port 4.
Next is the signal on port 8. 4.5/1.25 = 3.6
20 log of 3.6 = 11.1 dB
or
ratio of 3.6
Since this signal is 11.1 dB stronger than the signal on port 4,
the attenuator board on port 8 needs to be set to selection 5
(11 dB loss). This should put its signal at about 0.1 dB above
the signal of port 4.