Microchip Technology 4310B, User Manual

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CSIII (MODEL 4310B) User’s Guide
DS50003057A-page 28  2021 Microchip Technology Inc.
output signal characteristics, phase noise and stability, are determined by the
properties of the quartz oscillator. At longer times, the output signals reflect the
properties of the CBT.
The following
Figure 5-2 shows a block diagram of the CsIII.
FIGURE 5-2: Block Diagram of the CsIII .
The principal components of the CsIII include:
• A 5 MHz ovenized quartz oscillator that provides the reference for all outputs.
• An RF synthesizer that converts the 5 MHz reference up to the Cesium hyperfine
frequency, tunable around 9192631770 Hz.
• The Cesium beam tube (CBT), which produces an error signal proportional to the
detuning of the RF from the Cesium hyperfine resonance frequency.
• The microprocessor subsystem, that modulates the RF interrogation and steers
the quartz oscillator, implements additional servos for magnetic bias (C–) field,
microwave power, and signal gain, and monitors and reports system health
parameters.
• RF and 1 PPS output buffers.
• Cesium beam tube and other secondary power supplies.
5.2 CESIUM BEAM TUBE
The heart of the instrument is the Microchip Model 7610 Cesium Beam Tube (CBT).
The 7610 is a third generation CBT, reflecting 30 years of continuous manufacture and
improvement. The CBT is illustrated schematically in Figure 5-3 .