Abstract: A cross polarization compensation system, in which an input elliptically polarized wave is converted, by a first rotatable differential phase shifter having a phase shift of 90.degree. or less than 90.degree., into an elliptically polarized wave defined by.vertline..alpha..vertline.=.vertline.cot.sup.-1 .gamma..vertline.(where .alpha. is the tilt angle of an ellipse indicative of the elliptically polarized wave relative to a predetermined reference direction and .gamma. is the axial ratio for the ellipse), and then the phase delay or advance plane of a second rotatable differential phase shifter having a phase shift of the ellipse indicative of 90.degree. is disposed in alignment with the major axis of the converted elliptically polarized wave, thereby to obtain a linearly polarized wave having electric fields components of a desired direction.

Abstract: A cross polarization compensating system, in which two elliptically polarized waves of opposite polarities are applied to a cascade connection of two successively connected rotatable 90.degree. phase shifters and an Orthomode (Trademark) transducer. Two cross polarized wave components of the two elliptically polarized waves are detected from the two perpendicularly intersecting output terminals of the Orthomode (Trademark) transducer. Two in-phase components of the same phase as their co-polarized components of the two cross-polarized wave components and two orthogonal components each having a phase difference of 90.degree. from corresponding one of the co-polarized waves of the two cross-polarized wave components are detected from the two output terminals of the Orthomode (Trademark) transducer.

Abstract: A system for compensating for cross polarization coupling in a dual-polarization satellite communication system, in which two polarized waves of the same frequency and orthogonal to each other are alternately transmitted as a pilot wave from an earth station at a predetermined period. The same polarized wave components of the two signals received by a communication satellite are sent back to the earth station, so that the sent back signal is received by the earth station. An amplitude ratio and a phase difference between the same polarized wave components of the two signals of the received pilot signal are detected. A communication signal wave to be transmitted from the earth station is formed as an elliptically polarized wave by the use of the detected information, thereby compensating for cross polarization coupling of the communication signal wave caused during propagation between the earth station and the communication satellite.

Abstract: A transmultiplexer, in which after a pulse code modulated, time division multiplex signal of the voice band signal is converted into an analog signal, the analog signal is separated by filters into signals of respective channels and then the signals of the respective channels are combined together to provide a single sideband frequency divided, multiplex signal. In a reverse signal flow type, after a single sideband frequency-divided multiplex signal is separated by filters into signals of respective channels, the signals of respective channels are converted into digital signals and thereafter combined together to provide a pulse code modulated, time division multiplex signal. In accordance with this invention, a sign bit inverter is provided for reversing sign bits of predetermined specific channels in the pulse code modulated, time division multiplex signal every other frame.