Conventionally, PLL synthesizer receivers are generally configured as shown in FIG. 12. That is, with regard to a receiving circuit 21, a PLL circuit 22 for selecting the receiving frequency is provided, and the frequency dividing ratio of a programmable frequency divider of this PLL circuit 22 is controlled by a controlling means 23, and thereby receiving is performed at a desired receiving frequency. Numeral 24 designates an operating means for providing an operating input to the above-mentioned controlling means 23, numeral 25 designates a storing means for storing desired frequencies of radio broadcasting stations, and numeral 26 designates a display unit of frequency and the like. Here, the above-mentioned operating means 24 comprises a band key for selecting a frequency band for selecting a receiving frequency of a station, a station select key for incremeting and dicrementing the frequency, and further a memory key for writing to a preset memory, and read keys such as a scroll key for reading stored frequencies (or a select key of a required number of memories).
Then, a radio broadcasting station of a desired receiving frequency is selected and listened to by the band key of the operating means 24 and the station select key of the operating means 24, and the selected receiving frequency is written to the storing means 25 by the memory key to be set as a preset memory, and the preset receiving frequency is read by operating the read key, and thereby receiving can be conducted.
However, in the above-mentioned conventional receiver, the receiving-frequencies of the desired radio broadcasting stations are stored in advance in the storing means, and can be read at any time as required to be received promptly, but, for example, in the case where this receiver is used in another area on a private or business trip, the receiving frequencies of the radio broadcasting stations which have been preset in advance cannot be used, and a troublesome receiving operation has to be undertaken while searching the frequency of the radio broadcasting station in that area. At this time, where the frequency of the radio broadcasting station in that area is unknown, there is no means other than searching for the frequency while varying the frequency in sequence.