| 摘要 |
PROBLEM TO BE SOLVED: To simplify the structure of an oscillation circuit system and to attain reduction in current consumption and cost down by directly supplying a generated reference frequency to a transmission system for generating a transmission signal at an intermediate frequency. SOLUTION: A reference oscillator 46 generates the signal at a double frequency 2×Fif of an intermediate frequency Fif as a reference frequency Fref. The reference oscillator 46 supplies the signal at this reference frequency Fref to PLL frequency synthesizer circuits 41-45 and a 1/2 prescaler 35. The PLL frequency synthesizer circuits 41-45 input the signal at the reference frequency Fref and output a signal at a local oscillation frequency Flo. Further, the 1/2 prescaler 35 inputs the signal at the reference frequency Fref, divides that frequency into a 1/2 stage and generates a signal at the intermediate frequency Fif. Since the PLL frequency synthesizer circuits can be made into one, current consumption is reduced and the service life of a battery can be prolonged. |
