Development of low phase noise microwave frequency synthesizers for reducing Dick effect of Cs fountain clocks

effect of oral presentation on development of l2 learners grammar

this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...

Low-Phase-Noise, Low-Timing-Jitter Design Techniques for Delay Cell Based VCOs and Frequency Synthesizers

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, ...

Predicting the Phase Noise of PLL-Based Frequency Synthesizers

Version 4e, August 2006 A methodology is presented for predicting the phase noise of a PLL-based frequency synthesizer using simulation that is both accurate and efficient. The methodology begins by characterizing the phase noise behavior of the blocks that make up the PLL using transistor-level RF noise simulation. For each block, the phase noise is extracted and applied to a phase-domain mode...

Collisional frequency shifts in 133Cs fountain clocks.

We present a theoretical analysis of the density dependent frequency shift in Cs fountain clocks using the highly constrained binary collision model described by Leo et al. [Phys. Rev. Lett. 85, 2721 (2000)]. We predict a reversal in the clock shift at temperatures near 0.08 microK. Our results show that s waves dominate the collision process. However, as a consequence of the large scattering l...