Operator's Check - HP 85020 A Operating And Service Manual

Model 85020A/B
Operation
concerning exchange assemblies, refer to Section VI, Replaceable
Parts, of this manual.
3-9. The connectors are not separately replaceable. Because they
are precision connectors and have contact internally with the
bridge microcircuit, they cannot be repaired in the field. An
attempt to replace or repair the connectors will probably cause
damage to the bridge microcircuit. In addition, special fixtures
are required for reassembly. For repair or replacement of any
connector, return the 85020A/B to Hewlett-Packard.
3-10. OPERATOR'S CHECK
3-11. Figure 3-2 is an operator's check of the 85020A, which
allows the operator to make a quick check of the main system
functions prior to use. Figure 3-3 is an operator's check of the
85020B, The procedures cover the entire measurement system and
incorrect indications may be caused bv any portion of the system.
If the Directional Bridge is suspected, use the performance tests
in Section IV to determine if the bridge is working correctly. If
not, refer to Section VIII, Service, to isolate the problem.
3-12 - OPERATING INSTRUCTIONS
3-13. Instructions for operating the B5020A/B Directional Bridge
with the Model 8756A Scalar Network Analyzer are supplied in
Section III of the 8756A Operating and Service Manual. Fiqure 3-3
illustrates a typical instrument setup for transmission and
reflection measurements using the 85020A/B with the 8756A.
3-14. The 8755C Scalar Network Analyzer may be substituted for
the 8756A, with the addition of the 8750A Storage Normalizer in
applications where memory is required. In this case, the display
mainframe used with the 8755C may require modification for
interface with the 8750A. A table of 8750A/Displav Mainframe
compatibility is provided in Section I of the 8755C Operating and
Service Manual. Figure 3-4 shovrs a typical measurement setup using
the 8755C and the 8750A.
3-15. Ratio measurements can be obtained using a power splitter
in conjunction with the scalar network analyzer and detector(s).
Figure 3-5 illustrates a typical ratio measurement using a power
splitter.
3-16. 75-OHM OPERATION
3-17. For making measurements of 75-ohm devices usinq the 85020B,
two 50-ohm to 75-ohm minimum loss matching pads are required. One
of these is connected between the signal source and the inout port
of the 85020B. The other is connected between the device under
test and the il664A detector on the input of the Scalar Network
Analyzer,
3-3