Agilent Technologies 856290216 service manual Synthesizer Section, Synthesizer l-1

II

Synthesizer Section

The synthesizer section includes the A7 switched first LO distribution amplifier, the All YTO, and parts of the Al4 frequency control and Al5 RF assemblies. Simplified and detailed block diagrams for each assembly are located at the end of this chapter.

Troubleshooting Using the TAM

Troubleshooting Test Setup

Confirming a Faulty Synthesizer Section

General PLL Troubleshooting

PLL Locked at Wrong Frequency

Unlocked PLL

Unlocked Reference PLL (100 MHz VCXO)

Operation (100 MHz VCXO)

Troubleshooting (100 MHz VCXO)

Third LO Driver Amplifier (100 MHz VCXO)

Unlocked Reference PLL (600 MHz SAWR)

Operation (600 MHz SAWR)

Troubleshooting (600 MHz SAWR)

Third LO Driver Amplifier (600 MHz SAWR)

Unlocked Offset Lock Loop (Sampling Oscillator)

Operation

Troubleshooting

Unlocked YTO PLL

Operation

Troubleshooting an Unlocked YTO PLL

Unlocked Fractional N PLL

Operation

Confirming an Unlocked Condition

Fractional N PLL

Frequency Span Accuracy Problems

Determining the First LO Span

Confirming Span Problems

YTO Main Coil Span Problems (LO Spans >20 MHz)

YTO FM Coil Span Problems (LO Spans 2.01 MHz to 20 MHz)

Fractional N Span Problems (LO Spans 12 MHz)

First LO Span Problems (All Spans)

First LO Span Problems (Multiband Sweeps)

Synthesizer Section 1 l-1