Chapter 8
395
ADC/Interface Section
A3 Assembly Video Circuits
9. The Video MUX will appear faulty if A3CR109 is shorted or leaky.
Diode A3CR109 clamps the voltage at A3TP14 to
−
0.4 V when in log
expand with less than 0.8 V at J101. To confirm this failure, lift the
cathode of diode A3CR109 and perform steps 1 through 7 again.
10.To return the spectrum analyzer to automatic sweep, press
SWEEP
,
SWEEP CONT SGL
or press
PRESET
.
Video Filter
Refer to function block V of A3 Interface Assembly Schematic Diagram
(sheet 5 of 6) in the 8560 E-Series Spectrum Analyzer Component Level
Information.
The spectrum analyzer uses digital filtering for 1 Hz to 100 Hz video
bandwidths. An RC low-pass filter is used for 300 Hz to 3 MHz video
bandwidths. Various series resistances and shunt capacitances switch
into the video filter to change its cutoff frequency. The 3 MHz video
bandwidth is not available when Gated Video is selected.
When sample detection is selected, the effective video bandwidth is
limited to approximately 450 kHz by the track and hold circuitry.
When Gated Video is selected, the video signal is "gated" (turned on
periodically for a set duration of time). This function is shown in block
V of the block diagram as a series switch that allows the video signal to
pass only when it is closed. The actual switch, U109B/CR118, shunts
the video to ground (video signal is passed only when the switch is
open). The control circuitry for this switch is described under
“Triggering or Video Gating Problems” on page 385
EXT/GATE TRIG INPUT provides the connection for triggering in the
Gated Video mode. The gate output signal is available at the rear panel
BLKG/GATE OUTPUT connector. Positive or negative edge mode, or
level mode can be selected from the front panel.
1. Press
PRESET
and set the spectrum analyzer controls to the
following settings:
Center frequency ..................................................... 225 MHz
Span ......................................................................... 550 MHz
Sweep time ................................................ Uncoupled (MAN)
2. Press
CAL
and
IF ADJ OFF
.
3. Step the Video BW from 3 MHz to 10 kHz. At each step, the
peak-to-peak deviation of the noise should decrease.
4. Step the Video BW down to 1 Hz. At each step, the amplitude of the
LO feedthrough should decrease.
5. Refer to
and check for correct latched levels
for the selected video bandwidth setting.
Содержание 8564EC
Страница 17: ...25 1 General Information ...
Страница 37: ...47 2 Adjustment Diagnostic Software ...
Страница 55: ...Chapter 2 65 Adjustment Diagnostic Software 2 LO Frequency Figure 2 2 LO Frequency Adjustment Locations ...
Страница 57: ...Chapter 2 67 Adjustment Diagnostic Software 3 YTO FM Coil Figure 2 3 YTO FM Coil Adjustment Locations ...
Страница 77: ...89 3 Manual Adjustment Procedures ...
Страница 129: ...161 3a Manual Adjustment Procedures 3335A Source not Available ...
Страница 142: ...175 4 Assembly Replacement ...
Страница 151: ...184 Chapter4 Assembly Replacement Procedure 2 A1 Front Frame A18 LCD Figure 4 2 LCD Assembly Exploded View ...
Страница 163: ...Chapter 4 205 Assembly Replacement Procedure 5 A2 A3 A4 and A5 Assemblies Figure 4 10 Assembly Cables 2 of 3 ...
Страница 166: ...208 Chapter4 Assembly Replacement Procedure 5 A2 A3 A4 and A5 Assemblies Figure 4 14 GPIB and A1A1 W1 Cable Placement ...
Страница 168: ...210 Chapter4 Assembly Replacement Procedure 6 A6 Power Supply Assembly Figure 4 15 Power Supply Cover ...
Страница 176: ...226 Chapter4 Assembly Replacement A9 Input Attenuator Figure 4 22 A9 and A10 A12 Mounting Screws ...
Страница 179: ...Chapter 4 229 Assembly Replacement A11 YTO Figure 4 23 A11 Mounting Screws at Right Side Frame ...
Страница 183: ...Chapter 4 233 Assembly Replacement Procedure 8 A14 and A15 Assemblies Figure 4 25 A14 and A15 Assembly Cables ...
Страница 190: ...Chapter 4 243 Assembly Replacement Procedure 11 Rear Frame Rear Dress Panel Figure 4 29 A6 Power Supply Cover ...
Страница 194: ...Chapter 4 257 Assembly Replacement Procedure 13 A21 OCXO Figure 4 34 A21 OCXO Mounting Screws ...
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Страница 228: ...Chapter 6 307 Major Assembly and Cable Locations Introduction Figure 6 2 Top View A2 and A3 Unfolded ...
Страница 229: ...308 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 3 Top View A2 A3 A4 and A5 Unfolded ...
Страница 230: ...310 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 5 Bottom View A15 Unfolded ...
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Страница 233: ...314 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 9 Rear View FL4 B1 BT1 A20 VGA Connector ...
Страница 234: ...315 7 General Troubleshooting ...
Страница 238: ...Chapter 7 319 General Troubleshooting Introduction Figure 7 2 Ribbon Cable Connections 1 of 3 ...
Страница 239: ...320 Chapter7 General Troubleshooting Introduction Figure 7 3 Ribbon Cable Connections 2 of 3 ...
Страница 242: ...Chapter 7 323 General Troubleshooting Introduction Figure 7 5 Service Cal Data Menu ...
Страница 271: ...352 Chapter7 General Troubleshooting Block Diagram Description Figure 7 6 Functional Sections ...
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Страница 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
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Страница 322: ...427 9 IF Section ...
Страница 356: ...Chapter 9 461 IF Section A5 IF Assembly Figure 9 13 Detailed IF Adjust Signature 5 ...
Страница 358: ...Chapter 9 463 IF Section A5 IF Assembly Figure 9 14 Noisy Signature Figure 9 15 Noise with Correct Shape ...
Страница 359: ...464 Chapter9 IF Section A5 IF Assembly Figure 9 16 Region B Amplitude Variation Figure 9 17 Region B Amplitude Offset ...
Страница 369: ...474 Chapter9 IF Section Cal Oscillator P O A4 Assembly Figure 9 21 Output Waveform 10 kHz Resolution Bandwidth ...
Страница 370: ...Chapter 9 475 IF Section Cal Oscillator P O A4 Assembly Figure 9 22 Output Waveform 3 kHz Resolution Bandwidth ...
Страница 371: ...476 Chapter9 IF Section Cal Oscillator P O A4 Assembly Figure 9 23 Output Waveform 1 kHz Resolution Bandwidth ...
Страница 372: ...Chapter 9 477 IF Section Cal Oscillator P O A4 Assembly Figure 9 24 Output Waveform 300 Hz Resolution Bandwidth ...
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Страница 379: ...487 10 Controller Section ...
Страница 394: ...521 11 Synthesizer Section ...
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