| 摘要 |
PURPOSE:To measure the cross polarization of a transmission frequency band simply with a high precision, by detecting phase difference changing dependently upon the delay time between transmission and receiving and by adjusting automatically the low-frequency phase, which detects cross polarization components synchronously, by this phase difference signal. CONSTITUTION:The carrier wave generated by carrier wave generator 1 is applied to carrier wave residue modulator 2 and is modulated by the second low-frequency signal 30 of synchronizing circuit 24 to output residual carrier wave 27 and side band 28, and the carrier wave above is modulated in carrier wave suppression modulator 3 by the first low-frequency signal 31 of circuit 24 to output side band 29. Outputs of modulators 2 and 3 are applied to frequency converter 7 of the moving material through transmission antenna 5, and radio waves from converter 7 are received through receiving antenna 9 by the receiving unit and are applied to reference signal detector 16. Then, the second low-frequency signal 30 is separated and detected by phase detector 19, and further, signal 33 is delayed and applied to circuit 24, and phase difference of the second low- frequency signal 30 is measured, and signal 31 is added to this signal, and output signal 32 is applied to synchronous detectors 22 and 23, thus detecting cross polarization components synchronously. |
