Installation guide

Troubleshooting
Troubleshooting the AT1 High-Power Mechanical Attenuator (Option UNB)
1-83
NOTE Table 1-38 shows the amplitude levels and the corresponding attenuator control line voltages.
The amplitude levels are chosen so that they are approximately in the center of each 5 dB
switch point. Due to calibration variations, the absolute range of each 5 dB attenuation step
may have to be re-established. This can be accomplished by decreasing the power setting while
monitoring A23J25 pin 10. Note the power setting when the control line goes TTL-high (+5 V)
and continue decreasing the power and noting the power setting when the control line goes
TTL low (0 V). The difference in the two settings is the new range. Once a new range is
established, use the mid-point of each new range as the amplitude settings in place of the
settings in Table 1-38.
Table 1-38 Attenuator Control Lines and Corresponding Amplitude Levels
A23J25 Pin Numbers and Voltages
Amplitude Level
(dBm)
Pin 10
5dB Step
Pin 9
10 dB Step
Pin 6
20 dB Step
Pin 7
40 dB Step
Pin 5
60 dB Step
+2 00000
−3 +50000
−8 0+5000
−13 +5 +5 0 0 0
−18 00+500
−23 +5 0 +5 0 0
−28 0 +5 +5 0 0
−33 +5 +5 +5 0 0
−38 000+50
−43 +5 0 0 +5 0
−48 0 +5 0 +5 0
−53 +5 +5 0 +5 0
−58 0000+5
−63 +5 0 0 0 +5
−68 0+50 0+5
−73 +5 +5 0 0 +5
−78 0 0 +5 0 +5
−83 +5 0 +5 0 +5
−88 0 +5 +5 0 +5
−93 +5 +5 +5 0 +5
−98 0 0 0 +5 +5