41. The path difference, the difference in the distance traveled by each beam, creates a phase difference between them. 42. Both slabs are propagates through the second slab the phase difference is significantly decreased and even compensated for. 43. SAR makes use of the amplitude and the absolute phase difference or phase shift in the returning wave. 44. The system suffered from incompatibility with regular stereo playback due to phase differences between the left and right channels. 45. The amount of shift required to cause a significant phase difference is on the order of the wavelength used. 46. A phase detector is a nonlinear device whose output represents the phase difference between the two oscillating input signals. 47. In physics, two wave sources are perfectly coherent if they have a constant phase difference and the same frequency. 48. Each driver will measure the phase difference ( a distance in laps ) between him and the pace car. 49. A phase detector compares two input signals and produces an error signal which is proportional to their phase difference . 50. A rotating magnetic field can be constructed using two orthogonal coils with 90 degrees phase difference in their AC currents.
