622
Chapter 12
RF Section
A15 RF Assembly
3. Press
SGL SWP
,
CAL
,
IF ADJ OFF
.
4. Disconnect W29 (coax 7) from A15J601.
5. Connect a test cable from A15J601 to the input of another spectrum
analyzer.
6. Tune the other spectrum analyzer to 10.7 MHz. The signal displayed
on the other spectrum analyzer should be approximately
−
15 dBm.
7. Remove the test cable from A15J601 and reconnect W29 to A15J601.
Third Converter
Refer to function blocks A, B, C, D, and E on A15 RF Section Schematic
Diagram in the 8560 E-Series Spectrum Analyzer Component Level
Information.
The 3rd converter consists of the 2nd IF distribution, 2nd IF amplifier,
double balanced mixer, 10.7 MHz bandpass filter, and flatness
compensation amplifier. The 2nd IF distribution switches between two
possible 2nd IF inputs: the internally generated 2nd IF, or the external
mixing IF INPUT. A variable dc bias can be applied to the IF INPUT for
external mixers which require such bias. The selected input is fed to the
2nd IF Amplifier. This amplifier consists of four stages of gain and two
stages of SAW filters for image frequency rejection.
The flatness compensation amplifier consists of two fixed-gain stages
and two stages of variable gain. This provides an overall adjustable
gain of 4 dB to 30 dB. This gain is adjusted during a spectrum analyzer
sweep to compensate for front end conversion loss versus frequency.
The gain of the flatness compensation amplifiers is driven to a
minimum by the REDIR line going low during automatic IF
adjustment.
The 10.7 MHz bandpass filter provides a broadband termination to the
mixer while filtering out unwanted mixer products. Perform the
following steps to test the amplifier gain:
1. On the spectrum analyzer, press
AUX CTRL
, then
INTERNAL MIXER
.
2. In the 2nd IF distribution (function block A), diode CR802 should be
forward biased and diode CR801 should be reverse biased.
3. Disconnect W35 (coax 92) and connect a signal source to A15J801.
Set the source to the following settings:
Frequency ............................................................. 310.7 MHz
Amplitude ................................................................
−
30 dBm
Summary of Contents for 8564EC
Page 17: ...25 1 General Information ...
Page 37: ...47 2 Adjustment Diagnostic Software ...
Page 77: ...89 3 Manual Adjustment Procedures ...
Page 129: ...161 3a Manual Adjustment Procedures 3335A Source not Available ...
Page 142: ...175 4 Assembly Replacement ...
Page 194: ...Chapter 4 257 Assembly Replacement Procedure 13 A21 OCXO Figure 4 34 A21 OCXO Mounting Screws ...
Page 196: ...259 5 Replaceable Parts ...
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Page 223: ......
Page 224: ...303 6 Major Assembly and Cable Locations ...
Page 234: ...315 7 General Troubleshooting ...
Page 238: ...Chapter 7 319 General Troubleshooting Introduction Figure 7 2 Ribbon Cable Connections 1 of 3 ...
Page 239: ...320 Chapter7 General Troubleshooting Introduction Figure 7 3 Ribbon Cable Connections 2 of 3 ...
Page 242: ...Chapter 7 323 General Troubleshooting Introduction Figure 7 5 Service Cal Data Menu ...
Page 271: ...352 Chapter7 General Troubleshooting Block Diagram Description Figure 7 6 Functional Sections ...
Page 283: ...364 Chapter7 General Troubleshooting Block Diagram Description ...
Page 284: ......
Page 285: ......
Page 286: ......
Page 287: ...377 8 ADC Interface Section ...
Page 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
Page 321: ......
Page 322: ...427 9 IF Section ...
Page 356: ...Chapter 9 461 IF Section A5 IF Assembly Figure 9 13 Detailed IF Adjust Signature 5 ...
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Page 378: ......
Page 379: ...487 10 Controller Section ...
Page 394: ...521 11 Synthesizer Section ...
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Page 453: ......
Page 454: ...593 12 RF Section ...
Page 489: ...628 Chapter12 RF Section A15 RF Assembly Figure 12 10 10 MHz TTL Reference at U304 Pin 13 ...
Page 491: ......
Page 492: ...633 13 Display Power Supply Section ...
Page 504: ......
Page 505: ...671 14 Component Level Information Packets ...
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