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Polarization can be used to filter out unwanted signals, such as jamming. If a jammer and receiver do not have the same polarization, the jamming signal will incur a loss that reduces its effectiveness. The four basic polarizations are linear horizontal, linear vertical, right-hand circular, and left-hand circular.
Cross-polarization (CP), originally published as proton-enhanced nuclear induction spectroscopy (PENIS) [1] [2] is a solid-state nuclear magnetic resonance (ssNMR) technique to transfer nuclear magnetization from different types of nuclei via heteronuclear dipolar interactions.
Insensitive nuclei enhancement by polarization transfer (INEPT) is a signal enhancement method used in NMR spectroscopy. It involves the transfer of nuclear spin polarization from spins with large Boltzmann population differences to nuclear spins of interest with lower Boltzmann population differences. [ 1 ]
The most important method to counter radar jammers is operator training. Any system can be fooled with a jamming signal but a properly trained operator pays attention to the raw video signal and can detect abnormal patterns on the radar screen. The best indicator of jamming effectiveness to the jammer is countermeasures taken by the operator.
As the signal is stored in memory, it can be used to create false targets both behind (reactive jamming) and ahead of (predictive jamming) the target intended for protection. Slight variations in frequency can be made to create Doppler (velocity) errors in the victim receiver as well.
Consider the case of interaction of two perpendicularly polarized waves in nonlinear media with cubic nonlinearity. [1] The equations describing the self phase modulation of the fundamental wave A and the generation of new wave perpendicularly polarized wave B in condition that |B| << |A| (i.e. when the depletion of the fundamental wave is neglected, self and cross phase modulation of wave B ...
Polarization mode dispersion, polarization-dependent loss. and cross-polarization modulation are other phenomena that can cause problems in PDM systems. For this reason, PDM is generally used in conjunction with advanced channel coding techniques, allowing the use of digital signal processing to decode the signal in a way that is resilient to ...
The effect of jamming appears in the left "jagged" half of the circular ring, contrasting with the normal "smooth" (unjammed) display on the right half of the circle with a real target at the 3 o'clock position – on the jammed left side, the real target "blip" would have been indistinguishable from the jamming.