Patent ID: 6731704
Filing Date: 2004-05-04
Classification: H04B

Abstract:
An apparatus for eliminating interference of cross polarization, comprising:a signal demodulating section for receiving a first signal resulting from one of radio signals, which are transmitted in a modulated and encoded form respectively using two kinds of polarized plane waves intercrossing at right angles in a common frequency band, and for analog-to-digital converting, demodulating and equalizing the received first signal to output a first baseband signal; an interference eliminating section for receiving a second signal resulting from the other radio signal, analog-to-digital converting the received second signal to obtain a digital signal, delaying the obtained digital signal by a predetermined time, and demodulating and equalizing the resulting digital signal to output a second baseband signal; and an adding section for adding the second baseband signal from said interference eliminating section to the first baseband signal from said signal demodulating section to output a composite signal; said interference eliminating section including: analog-to-digital converter for converting the second signal to output a digital signal; a demodulator, connected to said analog-to-digital converter, for delaying the digital signal from said analog-to-digital converter by said predetermined time; an equalizer, connected to said demodulator, for equalizing the digital signal from said demodulator, and for extracting an amount of interference of cross polarization, said equalizer having a plurality of taps whose coefficients are variable for outputting of the second baseband signal; a controller, connected to said equalizer, for reading/writing the coefficients of said taps in said equalizer and outputting an amount of delay or precedence according to the amount of interference of cross polarization extracted in said equalizer as well as a control signal indicating an activation command or an inactivation command, about a baseband signal represented by the digital signal outputted from said analog-to-digital converter; and a timing adjuster, connected to said controller and said demodulator, for setting a delay time in said demodulator in accordance with said control signal from said controller.