| 摘要 |
PURPOSE:To eliminate the need for any detector for detecting oscillation of ships by individually measuring the phase difference between the output signals of the specific receiving element and other receiving elements, phase-shifting the output of a local oscillator by as much as said phase differences then supplying the same to the mixers corresponding to the receiving elements. CONSTITUTION:Vibrators T1, T2... of an ultrasonic wave receiver 1 are disposed respectively isolatedly on a straight line L1. The outputs of the respective receivers are sent out to a phase comparator 5 and mixers 6 thru 8. The phase comparator 5 compares the phases between the outputs of the amplifiers 2 and 3 as well as 2 and 4 and sends the phase difference signals to a phase shifter 9. The phase shifter 9 sends the output signal of an oscillator 10 directly to a mixer 6 and sends the phase- shifted output signal of the oscillator 10 to the mixers 7 and 8. The mixers 6 thru 8 mix the outputs of the amplifiers 2 thru 4 and the output of the phase shifter 9 and supply these outputs commonly to a filter 11. The filter 11 selects only the specific frequency components and allows the same to pass therethrough. |
