| 摘要 |
PURPOSE:To shorten a lock-up time while simplifying a circuit by using one voltage-controlled oscillator in common to more than one band. CONSTITUTION:Signals of frequencies obtained by multiplying oscillation output fv' of voltage-controlled oscillator 12' by multiplying circuits 18a and 18s with multiplication ratios Ma and Ms are applied to mixing circuits 2a' and 2s' by way of LPFs 19a and 19s. On the other hand, output fv' of oscillator 12' is multiplied by M at multiplying circuit 20 and, after being frequency-divided by programmable frequency dividing circuit 13', compared with reference frequency fr' by phase comparing circuit 14'. In this circuit constitution, setting multiplication ratios Ma Ms and properly makes it possible to use oscillator 12' without reference to the band. In Europe, etc., reference frequency fr' can be set high, so that the lock-up time can be shortened. |
