Chapter 7
357
General Troubleshooting
Block Diagram Description
Synthesizer Section
The 1st LO is phase-locked to the 10 MHz standard internal to the
instrument by four PLLs. See
The reference PLL supplies reference frequencies for the instrument.
The three remaining PLLs tune and phase-lock the LO through its
frequency range. To tune the LO to a particular frequency, the
instrument microprocessor must set the programmable feedback
dividers (N) and reference dividers (R) contained in each PLL.
Sweeping the 1st LO
The spectrum analyzer uses a method called lock and roll to sweep the
1st LO (A11 YTO) for LO spans >2 MHz. This involves phase-locking
the spectrum analyzer at the start frequency during the retrace of the
sweep, then sweeping through the desired frequency range in an
unlocked condition. The sweep ramp, which sweeps the LO during the
roll part of the lock and roll process, is generated on the A14 frequency
control assembly. It is applied to either the main coil or the FM coil of
the A11 YTO. For LO spans
≤
2.0 MHz, the YTO PLL remains locked and
the fractional N PLL sweeps while remaining phase locked. The
frequency/span relationships are as follows:
When the sweep ramp is applied to the YTO, the spectrum analyzer
must prevent this loop from trying to compensate for changes in the
output frequency. To accomplish this, the spectrum analyzer opens the
PLL by disconnecting the YTO PLL phase detector output.
Reference PLL (part of A15)
The 100 MHz PLL output is routed through multipliers to provide
600 MHz for the second LO, and 300 MHz for the third LO and the
sampling oscillator reference.
The reference PLL is also divided down to 10 MHz
for the fractional N PLL. The reference PLL is locked to a 10 MHz
OCXO (oven-compensated crystal oscillator) or a TCXO (Option 103).
The PLL can also be locked to an external frequency reference.
The 10 MHz reference also supplies the reference for the frequency
counter on the A2 controller assembly, and the cal oscillator on the A4
assembly.
A11 YTO Spanwidth
Sweep Applied To
20.1 MHz to 3.8107 GHz
A11 YTO main coil
2.01 MHz to 20.0 MHz
A11 YTO FM coil
100 Hz to 2 MHz
Fractional N phase locked
loop
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 ...
Страница 196: ...259 5 Replaceable Parts ...
Страница 218: ......
Страница 219: ......
Страница 220: ......
Страница 221: ......
Страница 222: ......
Страница 223: ......
Страница 224: ...303 6 Major Assembly and Cable Locations ...
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 ...
Страница 231: ...Chapter 6 311 Major Assembly and Cable Locations Introduction Figure 6 6 Bottom View A15 and A14 Unfolded ...
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 ...
Страница 283: ...364 Chapter7 General Troubleshooting Block Diagram Description ...
Страница 284: ......
Страница 285: ......
Страница 286: ......
Страница 287: ...377 8 ADC Interface Section ...
Страница 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
Страница 321: ......
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 ...
Страница 376: ......
Страница 377: ......
Страница 378: ......
Страница 379: ...487 10 Controller Section ...
Страница 394: ...521 11 Synthesizer Section ...
Страница 431: ...564 Chapter11 Synthesizer Section Unlocked Fractional N PLL Figure 11 8 VCO Bias Voltages for A14 Assemblies ...
Страница 447: ...Chapter 11 581 Synthesizer Section Sweep Generator Circuit Figure 11 11 Simplified Synthesizer Section ...
Страница 448: ...582 Chapter11 Synthesizer Section Sweep Generator Circuit Figure 11 12 Simplified A14 Assembly Block Diagram ...
Страница 451: ......
Страница 452: ......
Страница 453: ......
Страница 454: ...593 12 RF Section ...
Страница 475: ...614 Chapter12 RF Section A14 Frequency Control Assembly Figure 12 4 A7 LO Multiplier Amplifier Drive ...
Страница 489: ...628 Chapter12 RF Section A15 RF Assembly Figure 12 10 10 MHz TTL Reference at U304 Pin 13 ...
Страница 491: ......
Страница 492: ...633 13 Display Power Supply Section ...
Страница 504: ......
Страница 505: ...671 14 Component Level Information Packets ...
Страница 507: ......