RADIO RECEIVER

PURPOSE:To decrease the number of parts and to reduce a cost, by providing one ceramic filter, making a band of the filter variable, and switching and using the band in the course of automatic channel selection and thereafter. CONSTITUTION:When automatic channel selection is being executed, a muting output (d) from a PLL synthesizer control part 11 is supplied to the base of a transistor 12, it becomes a cutoff state, capacity C of a coupling capacitor of a ceramic filter 5 becomes C=C2 (capacity of a capacitor 14), and a passng band characteristic becomes a curve of a narrow band. Accordingly, a trigger signal (c) is fetched from the ceramic filter 5 by a band decided by C2, and when a signal radio wave is detected, the PLL becomes a locked state and becomes receivable. In this case, as soon as the signal radio wave is received, the muting output (d) from the PLL control part 11 is changed as ''L H'', the transistor 12 becomes a conducting state, and as for the band characteristic, a ceramic filter for a wide band, namely, regular intermediate frequency is obtained.