phase coherence


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phase coherence

A term used in MRI referring to the degree to which precessing nuclear spins are synchronous—i.e., the degree to which the peaks and troughs
of their waveforms coincide.
References in periodicals archive ?
As applied to frequency synthesizers, phase coherence describes the relation of the frequency standard to the output frequency.
Equipped with the R&S SMW-B90 phase coherence option, it can phase lock modulated or unmodulated signals.
The module features a high-stability internal reference, which can be phase-locked to a user-configurable external reference or used in a master-slave configuration for highest phase coherence.
Key features of the APSYN420B include low phase noise, fast switching (settling time is typically 20 is with a frequency update rate of 200 is), low phase noise, and an internal OCXO reference that can be configured for high phase coherence between multiple sources.
Our measurements give the most definitive spectroscopic evidence that the material we studied is a superconductor, even above the transition temperature, but one without the quantum phase coherence required for current to flow with no resistance," said physicist Seamus Davis of the US Department of Energy's (DOE) Brookhaven National Laboratory and Cornell University, who led the research team.
The spectral purity of its output, its phase coherence and its ability to switch frequency at sub-microsecond rates make the synthesizer the ideal signal source for threat and target simulations.
When switching from one frequency to another and then back again, the instrument preserves phase coherence with the original signal.
A new Multisynch timing sub-system provides frequency and phase coherence between analog and digital instrumentation, and unique "what if" software tools allow engineers to find and correct functional and performance errors root cause analysis.
Especially when using the CW version, the combination of R&S SGS100A and R&S SGU100A is optimal for multitone applications requiring phase coherence.
Phase coherence, that is a stable phase relationship between signals, is essential when making measurements that require more than one RF output.
Using the analogy of time, Table 2 shows the phase coherence for each of the four elements of Figure 1.