High-speed method for finding an alternative frequency in a radio system

摘要

A high-speed processing method in a ratio data system which is capabe of searching an alternative frequency of other broadcasting stations which are sending out the same program when the field strength of the currently received broadcasted signal becomes weaker. The method is excecuted by sorting an alternative frequency list, searching an alternative frequency in order in the alternative frequency list when an intermediate frequency level meter signal of the received braodcasted signal is maintained below a predetermined level, outputting rising or falling control pulse to increase or decrease a tuning voltage instantly, setting the alternative frequency as a reference frequency of the phase-locked loop, storing in order the intermediate frequency level meter signal of the currently received broadcasted signal only when it is greater than a predetermined level, searching a highest signal among the stored intermediate frequency level signals, and then setting the alternative frequency in response to the highest signal as a reference signal of the phase-locked loop. IMAGE