| 摘要 |
PURPOSE:To prevent the production of tracking error, by using separate PLL circuits for local signal frequency and tuning voltage for RF amplifier. CONSTITUTION:PLL circuits 6, 8 are provided and a controller 7 and a reference oscillator 61 are used in common. The output of the PLL circuit 8 is applied to an RF amplifier, and the output of the PLL circuit 6 is applied to a mixer MIX3. The frequency dividing ratio of frequency dividers 82, 62 is changed. For example, taking the RF reception frequncy fr as 531-1602kHz, frequency between stations as 9kHz(=fs), RF signal frequency as 468kHz, local signal frequency f as 999(531+468)-2070(1602+468)kHz and frequency fs of a reference oscillator 61 as 9kHz, respectively, the relation among the frequency dividing ratio N of the frequency divider 62 and the frequency dividing ratio N' of the frequency divider 82 is N'=N-52. |
