Agilent Technologies HP 8566B Spécifications télécharger pdf (Page 286)

17.

20/30

Loop

Phase

Lock

Adjustments

Reference

RF-Section:

A10

20/30

Synthesizer

AlOAl PLLl VCO

AlOA3

PLLl

AlOA4

PLL3 Up Converter

AlOA5

PLL2

VCO

A 1 OA8

PLL2

Discriminator

Description

Phase

Lock

Loop

(PLU):

On the AlOAl PLLl VCO Assembly, the

Loop Amplifier 40

kHz

LPF is first adjusted for

>65

rejection of

the 50

kHz

subharmonics from fractional-n division. A frequency

synthesizer is used to inject a signal into the 40

kHz

LPF, and the filter

output is measured with a spectrum analyzer using a high-impedance

active probe. Then, the centering and tuning range of the

PLLl

VCO is checked and adjusted as required. On the

AlOA3

PLLl

Assembly, the 140 MHz Lowpass Filter is checked and adjusted for

maximum rejection of mixing products between 160 MHz and 166

MHz. A synthesized sweeper is substituted for the

PLLl

VCO, and the

output of the

AlOA3

PLLl

IF Assembly is measured with a spectrum

analyzer.

Phase

Lock

Loop

(PLU):

On the

AlOA5

PLL2

VCO Assembly

and A10A8

PLL2

Discriminator Assembly, four interactive biasing

adjustments are used to set the centering and tuning range of the

PLL2

VCO.

PLL2

VCO biasing is adjusted by setting up proper voltage

levels at

AlOA8TP5

VCO TUNE and adjusting for corresponding

PLL2

VCO frequencies at AlOA5J4 (SCAN

1.1

MHz OUT). If

PLL2

will not

phase lock (PL2 UNLOCK indicated), the

AlOA6

PLL2 Phase Detector

Assembly is first disabled for coarse biasing adjustments. Fine biasing

adjustments of the

PLL2

VCO are made with the

AlOA6

PLL2

Phase

Detector Assembly installed. Then, span accuracy for narrow spans is

checked and adjusted by positioning the 100 MHz CAL OUTPUT signal

on the 9th CRT graticule line.

Phase Lock Loop

(PIL3):

On the

AlOA4

PLL3 Up Converter

Assembly, the 160 MHz BPF is adjusted for maximum output of the

1.6 Frequency Multiplier. The

PLL3

VCO biasing is then adjusted by

setting up proper voltage levels at

AlOA4TP3,

and the PLL3 VCO

output power level is verified.

3.146 Adjustments

1 2 ... 281 282 283 284 285 286 287 288 289 290 291 ... 404 405

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Agilent Technologies HP 8566B Spécifications Page 286

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