#PHASE COHERENCE GENERATOR#
Different generator models can be coupled to optimally fit user requirements in terms of number of phase coherent channels and RF frequency range. Note that this is different from (usually shorter than) the time constant $T_1$ for the dipoles to decay back to be aligned on the $z$ axis. The generators’ phase coherence option enables LO coupling of multiple instruments by distributing the synthesizer signal of one instrument to the others. The time constant for this exponential fall is called $T_2$. known as phase coherence imaging (PCI), presents certain advantages, including the following: Only the instantaneous phase of the signal is considered, and material attenuation does not affect the phase of the signal, so PCI could be particularly helpful in resolving the challenges of thick or highly attenuative material inspection applications.
So immediately after the pulse we measure a strong signal, but as the dipoles spread out in the $xy$ plane they start cancelling each other out and the strength of the signal we measure falls in a roughly exponential fashion. Phase coherent imaging (PCI) in image processing mode has been applied to other fields by other scholars due to its excellent performance 18 1920212223. This means that although they start out all pointing in the same direction (along the $x$ axis) they end up orientated randomly in the $xy$ plane so the net dipole is zero and we can no longer measure it. The trouble is that the dipoles are all of slightly different strengths and so they all rotate at slightly different speeds. The spins now start rotating in the $xy$ plane and we measure the frequency of rotation to get the dipole moment. In pulsed NMR we start with the dipoles all aligned with the magnetic field (call this the $z$ axis) then we apply a pulse to rotate all the dipoles onto the $x$ axis i.e.
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