| 摘要 |
PURPOSE:To attain ease of adjustment of pass band by generating program information at the 1st and 2nd program information generation means and inputting an integrating pulse to the said means from a pulse generation circuit to activate/inactivate a pulse integrating function as the generation means thereby adjusting the pass band. CONSTITUTION:Pulse integrating counters 26-28 as the 1st and 2nd program information generating means are provided. The said generated information is outputted to counters 23a-25a of PLL circuits 23-25. An adding subtracting pulse is fed to counters 26, 27 from a frequency adjusting dial 20 and a pulse generator 16. Since the frequency passing through a BPF4 is shifted more than the normal case by the PLL circuit 24 and the frequency of an oscillated signal of a mixer 5 is shifted similarly, the frequency is restored to the normal frequency, resulting in that the pass band of the BPF4 is shifted. Since the pass frequency band of a BPF6 is changed by the said shift's share in this way, the said increase/decrease is decided in a direction to narrow the pass band. Moreover, the frequency of the oscillated signal of a demodulator 7 and a mixer 3 is increased/decreased by the operation of a shift button 22. The frequency band for the BPF4, the mixer 5 and the BPF6 is unchanged in this case, thereby conducting the shift operation only. |
