| 摘要 |
PURPOSE:To eliminate effectively the disturbance wave, by feeding the result of addition of outputs of two receiving antennas and the result of subtraction received a 90 deg. phase shift after a synchronous wave detection of both results. CONSTITUTION:The disturbance waves received through receiving antennas 3 and 4 are added 23 together via distributors 21 and 24, and the result of this addition is sent to an adder circuit 29. These disturbance waves also undergo subtraction 22, and the output of subtraction is distributed 26 after a 90 deg. phase shift 25. One of these two disturbance waves is applied to a variable gain amplifier 27; and a prescribed band component of the other wave is applied to a synchronous wave detector 31 via a BPF32 and in the form of a reference signal after amplification 28. At the same time, the sum signal is added to a differenctial output through an adder circuit 29. If a residual component arises to the sum signal, the signal is fed to the detector 31 through a distributor 30 to receive a synchronous wave detection with the supplied reference signal. Then a DC component signal corresponding to the amplitude of the residual disturbance component is obtained from the detector 31, and the output of the DC component signal controls the amplifier 27 through an LPF33. |
