260 Chapter5
Troubleshooting the IF Section
IF Power-Level Measurement
To check bandwidth control lines for the A11/A13
bandwidth filter assemblies
Table 5-1 provides nominal bandwidth control voltages sent to the A11
and A13 bandwidth filter assemblies from the A7 analog interface
assembly. A calibrated analyzer produces control voltages similar to the
values in Table 5-1. (The values in Table 5-1 were measured while
default calibration data was in use.)
• Use the difference in control voltage between bandwidths from the
table as a guide for normal bandwidth operation.
• Use an extender board to measure the bandwidth control voltages at
the motherboard connector for the A7 assembly or the A11/A13 filter
assemblies.
• Refer to “Troubleshooting the A15 Motherboard Assembly” for the
location of the control lines for each assembly.
Table 5-1 Nominal Resolution Bandwidth Control Line Voltages
Resolution
Bandwidth
BW5 BW6 BW7
3 dB
5 MHz +14.0 −9.90 +4.4
3 MHz +14.0 −9.90 +6.4
1 MHz +14.0 −9.90 +8.5
0.3 MHz +14.0 −9.90 +9.4
0.1 MHz +14.0 −9.90 +9.7
30 kHz −1.0 +9.25 +9.7
10 kHz −1.0 +8.96 +9.7
3 kHz −1.0 +8.51 +9.7
1 kHz −1.0 +7.50 +9.7
0.3 kHz −1.0 +6.00 +9.7
6 dB EMI
9 kHz −1.0 +8.81 +9.7
120 kHz +14.0 −9.90 +9.6
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