| 摘要 |
One of outputs of reference frequency sources 11 and 12 is selected by a switch 13, as a reference frequency signal and compared with the phase of an output of a frequency divider 19 by a phase comparator 14. A voltage controlled oscillator 16 is controlled by a result of comparison. An output of the voltage controlled oscillator 16 and an output of another reference frequency source 18 are mixed by a mixer 17. An upper side band frequency signal of the mixer 17 is used as an output of the multiple PLL oscillator, and a lower side band frequency signal of the mixer 17 is supplied to the frequency divider 19. With the configuration, in the multiple millimeter PLL oscillator, even when the dividing number of frequency increases, lock-up time to reach a desired frequency can be shortened. Thus, stability of a PLL can be improved and specifications of the oscillation frequency of the millimeter wave band and a step frequency of hundreds kHz can be realized. The invention is adapted to an oscillator for a two waves millimeter wave radar.
|
