Installation guide

Troubleshooting
Troubleshooting the AT1 Electronic Attenuator (Option 501, 502, 503, 504 or Option UNJ)
1-80
NOTE Table 1-36 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 9. 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 1-36.
Table 1-36 Attenuator Control Lines and Corresponding Amplitude Levels
A23J25 Pin Numbers and Voltages
Amplitude Level
(dBm)
Pin 4
5dB
Step
Pin 9
5dB
Step
Pin 6
10 dB
Step
Pin 7
10 dB
Step
Pin 3
20 dB
Step
Pin 5
40 dB
Step
Pin 10
40 dB
Step
+0 0000000
−5 +5000000
−10 +5+500000
−15 +50+50000
−20 +5+5+50000
−25 +50+5+5000
−30 +5 +5 +5 +5 0 0 0
−35 +5 0 +5 0 +5 0 0
−40 +5 +5 +5 0 +5 0 0
−45 +5 0 +5+5+5 0 0
−50 +5 +5 +5 +5 +5 0 0
−55 +50+50 0+50
−60 +5 +5 +5 0 0 +5 0
−65 +5 0 +5 +5 0 +5 0
−70 +5 +5 +5 +5 0 +5 0
−75 +5 0 +5 0 +5 +5 0
−80 +5 +5 +5 0 +5 +5 0
−85 +5 0 +5+5+5+5 0
−90 +5 +5 +5 +5 +5 +5 0
−95 +50+50 0+5+5
−100 +5 +5 +5 0 0 +5 +5