| 摘要 |
PURPOSE:To extend an interval between an antenna up to the one wave length of a radio wave by discriminating a real phase difference range by comparing the absolut value and threshold value of the difference between output phases of two receivers due to two sets of antenna which are successively switched. CONSTITUTION:The outputs of two receivers from terminals T1 and T2 are processed at an inverter G1 and AND gate G2 and a real advanced and delayed phase difference signals of the interval of + or -180 deg. are impressed upon AND gates G4 and G6. On the other hand, the inversion of the advance and delay of a phase difference due to the change over of two sets of antennae installed on the circumference of a circle at a regular interval is detected by an FF21 and, at the same time, it is discriminated at another FF22 that whether or not the phase difference after switching the antennae exceeds a threshold of 90 deg.. Then the advance and delay of the absolute values of phase differences, at which detected phase differences discontinue, are discriminated by an FF29 and the AND gates G4-G7 are controlled. By means of these arrangements, the real phase differences of ranges of + or -180 deg., +180-+360 deg., -180--360 deg. are discriminated and the antenna interval can be extended up to one wave length of a radio wave and, therefore, to reduce errors in direction finding. |
