| 摘要 |
PURPOSE:To attain a high accuracy azimuth measurement even in a narrow band transmission line whose frequency band is limited, by transmitting a signal of direction finding having a muting point by applying it to band compression by turning-back the muting point, and expanding it to its original waveform at the receiving end. CONSTITUTION:A high frequency signal induced in an antenna 11 is converted to a balanced molulated wave having a muting point by a goniometer 12, a detecting signal (b) being a full wave rectifying signal having a muting point is obtained by a receiver 13 and a detector 14, it is supplied to each terminal of a switching device 19 through a same phase buffer 15, opposite phase buffer 16 and a muting point detector 17 and an FF circuit 18, respectively, and in this state, a switching-synthesized output signal (g) is inverted as to its phase at the muting point, and the band is compressed. Subsequently, said signal is transmitted to the receiving end through a synthesizer 22A and a circuit 22B by a frequency modulator 20 and a band pass filter 21. In the receiving end side, the frequency modulating signal transmitted from the circuit 22B is demodulated by an FM demodulator 24 from a band pass filter 23, multiplied by the output from a frequency oscillator at a multiplier 25, and goes to an artificial balanced modulated wave. |
