| 摘要 |
PURPOSE:To make a cycle selection through simple constitution by using one low-Q band-eliminating filter. CONSTITUTION:A loran signal induced at an antenna is received by a receiver part 1 and used as a loran pulse signal of carrier wave frequency f0 with an envelope waveform (a) shown by (e1), which is inputted to a BPF7. The loran signal after having the carrier wave removed by the BPF7 has an envelope waveform (b) as shown by (e2) and also shifted in phase in the carrier wave at P3. Then the phase shift point of the carrier wave like P3 contacts a lateral axis when the removal frequency of the BPF7 coincides with the frequency f0, and the phase shift point is selected normally at the 3rd cycle for loran C or near a point about a half a maximum value for loran A. Thus, the phase shift point is selected at an optional position by varying the elimination band width of the BPF7. Namely, the phase shift point is set at optional points in every half cycle like P1, P2-P5. Then, the waveform (e2) is shaped into (e3) through a waveform shaping circuit 6. |
