| 摘要 |
PURPOSE:To improve the frequency characteristic by performing the phase control of a carrier contained in a side band power so as to form the same negative feedback phase control loop regardless of period responding to the polarity of a differential composite signal waveform of navigation low frequency signal in a modulation circuit of an ILS ground station for guiding the approach of an aircraft to an air port. CONSTITUTION:A phase switching circuit 2 sends a phase adjusting carrier 101 to a transmission power amplification circuit 4 as phase 0, pi switching carrier 201 through an AM modulation circuit 3 with a switching according to a phase switching pulse 1,102 of a phase switching generation circuit 11 receiving a differential composite signal 2501A between 90Hz and 150Hz and a side band power 401 is sent out. The side band power 401, is inputted into a phase detection circuit 6 and controlled through a negative feedback circuit made up of phase detection output switching circuit 8, a phase detection output amplification circuit 9 and a phase adjustment circuit 1. |
