Abstract: A receiving frequency selecting method for a vehicle-mounted RDS receiver, wherein a list of alternative frequencies being transmitted by former broadcasting stations are stored in a memory, and the RDS receiver chases the same broadcast program based on the stored list of alternative frequencies whenever the motor vehicle returns to the same broadcasting service area of the network wherein the stored list of alternative frequencies is effective for use. Further, the stored list of alternative frequencies data relating to frequencies of the received broadcast waves during the operation of chasing the same radio program are also utilized together with the stored list of alternative frequencies transmitted by the broadcasting stations for chasing the same broadcast program.

Abstract: An electronic circuit device having an electric-code locking functions so that when the electronic circuit device is electrically connected to a battery, a control circuit is activated to cause a power supply detecting circuit to detect whether the electronic circuit device has been stolen. When a proper code is input by a control input unit after the completion of its detection, the electronic circuit device can be normally operated. In response to another simple operation signal input from the control input unit, the control circuit controls a radio receiving circuit, a tape circuit and a muting circuit in such a manner that the electronic circuit device is temporarily brought to the normal operation state. That is, the electronic circuit device can be provided with an additional function for temporarily bringing the electronic circuit device to an operation state by inputting an operation signal other than a signal indicative of a mnemonic in order to improve the efficiency of its fabrication.

Abstract: An automatic broadcast wave tuning device for a RDS receiver includes a controller to enforce the RDS receiver to receive the former broadcast wave by setting a forbidden flag under such conditions as being unable to receive a program identification code when a receiving signal level of the broadcast wave within the same broadcasting network is above a predetermined signal level, or in the case of being able to receive the program identification code when failing to meet up with that of the broadcasting station presently in contact. Hence, from the next automatic receiving frequency tuning, a control is provided for setting a frequency divisional ratio of the phase-locked loop circuit in order to select the best broadcast station of all by discriminating reception signal levels of the broadcast waves transmitted by all the broadcasting stations bearing no forbidden flag.