10-15 Frequency Stability Microwave Synthesizer for Atomic Fountain Frequency Standard

Development of Cs Atomic Fountain Frequency Standard at CRL

Communications Research Laboratory (CRL) has been conducting the development of a Cesium atomic fountain primary frequency standard. Cs atoms are collected in a MOT and in optical molasses. They are further cooled to 2μK by PGC, and launched to a height of 30cm above the microwave cavity by moving molasses method. The launched atoms interact with the microwave twice, going upward and downward, ...

Realisation of a Frequency Standard Using an Atomic Fountain *

We report the realisation and preliminary study of a frequency standard using a fountain of laser cooled caesium atoms. Our apparatus uses a magneto-optical trap as a source of cold atoms and optical pumping to prepare the atoms in the correct state before they enter the microwave cavity.

Quantum Projection Noise in an Atomic Fountain: A High Stability Cesium Frequency Standard

We describe the operation of a laser cooled cesium fountain clock in the quantum limited regime. An ultrastable cryogenic sapphire oscillator is used to measure the short-term frequency stability of the fountain as a function of the number of detected atoms Nat. For Nat varying from 4 3 104 to 6 3 105 the Allan standard deviation of the frequency fluctuations is in excellent agreement with the ...

A Standard Cell-Based Frequency Synthesizer with Dynamic Frequency Counting

SUMMARY This paper presents a standard cell-based frequency synthesizer with dynamic frequency counting (DFC) for multiplying input reference frequency by N times. The dynamic frequency counting loop uses variable time period to estimate and tune the frequency of digitally-controlled oscillator (DCO) which enhances frequency detection's resolution and loop stability. Two ripple counters serve a...

An experimental study of intermodulation effects in an atomic fountain frequency standard