| 摘要 |
PURPOSE:To make it possible to receive a priority channel signal while receiving an unpriority channel signal by selecting two kinds of PLL data using a rotary switch which can be operated at the 1st and 2nd positions coaxial. CONSTITUTION:A RF signal is tuned and amplified by RFAMP1, and converted into 1st and 2nd IFs by 1st and 2nd MIXes 2 and 3 at a local oscillation frequency from PLL synthesizer circuit 4, thereby driving speaker SP by way of 2nd IFAMP5, AM detector 6 and power amplifier 7. The 1st local oscillation uses the local oscillation of the PLL synthesizer, whose frequency is varied by controlling a programmable counter by varying a binary code. This code is set by main-channel data selecting method 8 and desirable-channel data selecting method 8' respectively. It is made possible to turn and select rotary switch SR before and after the axis and a desirable channel is connected to PLL via data change-over circuit 9. |
