MEDIUM WAVE SUBORDINATE SYNCHRONIZATION BROADCASTING SYSTEM

摘要

PURPOSE:To eliminate reception disability due to the change of a phase difference by using the synchronizing signal of a frequency 9KHz and comparing a phase on the side of a broadcasting station at the frequency 9KHz. CONSTITUTION:The synchronizing signal from a synchronizing signal 9KHz crystal oscillator 1 and a program signal from a program signal input terminal 2 are synthesized in a multiplex modulator 3, and outputs are transmitted to broadcasting stations A and B by an STL transmitter 4. In the broadcasting stations A and B, STL receivers 5 receive the signals and multiplex demodulators 6 separate the program signal and the synchronizing signal of 9KHz. The synchronizing signal of 9KHz is directly added to 9KHz phase comparators 7. On the other hand, frequency dividers 9 count down a part of the output of VCO8, which is added to the phase comparators 7 with the synchronizing signal, the phase difference of both is detected, and the voltage of VCO8 is controlled, whereby a carrier which is completely synchronized with the frequency 9KHz of the synchronizing signal can be obtained in the broadcasting stations A and B. Thus, the phase difference in equal electric field areas are eliminated and phase fluctuation can be settled.