PURPOSE: To prevent the variable range of a low band tuning frequency from becoming narrower and to prevent the reduction of Q of a tuning circuit by selecting low or high band tuning amplifier stage with a band selector switch.
CONSTITUTION: A low band tuning amplifier stage TA1 is provided with a 1st input tuning circuit 1L, a 1st high frequency amplifier circuit 2L and a 1st inter-stage tuning circuit 3L corresponding to the reception of a low band. Moreover, a high band tuning amplifier stage TA2 is provided with a 2nd input tuning circuit 1H, a 2nd high frequency amplifier circuit 2H and a 2nd inter- stage tuning circuit 3H corresponding to the reception of a high band. Then selection sections SW1, SW2 selecting the low band tuning amplifier stage TA1 at the reception of a low band and selecting the high band tuning amplifier stage TA2 at the reception of a high band respectively are provided. Thus, a switching diode for selecting the low band and the high band is not required and a problem such as narrowed tuning range in the low band tuning frequency due to the off capacitance or the Q deterioration of the tuning circuit due to the ON resistance is avoided.
KASAGI TADASHI
SAITO YUTAKA
| JP46022691A | ||||
| JP46022692A | ||||
| JP49105012B |