CROSS POLARIZED WAVE INTERFERENCE ELIMINATION CIRCUIT

• Main Author: TAWARA MASATO
• Format: Patent
• Language: English
• Published: 30.09.1991
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; MULTIPLEX COMMUNICATION

PURPOSE:To suppress leakage of an excess level interference signal of a different polarized wave side onto a main polarized wave demodulation system and to prevent deterioration in the characteristic by providing a signal suppression circuit to an input or an output side of a transversal filter and suppressing an input signal or an output signal of the transversal filter at a fault of a different polarized wave signal. CONSTITUTION:One signal (main polarized wave signal) in orthogonal two polarized wave reception signals is subject to demodulation processing by a demodulator 3 via an input terminal 1 and the other signal (different polarized wave signal) is subject to demodulation processing by a demodulator 4 via an input terminal 2. A variable attenuator 7 being a signal suppression circuit is interposed between an output of a transversal filter 5 and an input of the demodulator 3 and the attenuation is controlled by a reset signal 9. When the demodulator 4 at the different polarized wave side gives an abnormal output due to extreme level reduction or noise increase resulting from fading and occurrence of an interference signal of a high level such as a radar signal, a different polarized wave signal abnormity detection circuit 8 generates a reset signal 9 to reset the transversal filter 5 and the variable attenuator 7 receives the reset signal 9 to maximize its attenuation.