| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronizing signal generating apparatus 10 capable of suppressing incapability of generating a transmission wave with an instructed frequency by avoiding spurious radiation. <P>SOLUTION: An oscillated signal from a reference oscillator 11 is fed to a PLL unit 18 via a frequency divider 12, a multiplier 13, and a DDS 14. In the PLL unit 18, the transmission wave at an output terminal 185 is fed back to a phase comparator 182 via a frequency divider 186, and the phase comparator 182 detects a phase difference between a signal from the DDS 14 received via an R counter 181 and a signal from the frequency divider 186. The PLL unit 18 forms the transmission wave on the basis of the phase difference detected by the phase comparator 182. A frequency division ratio N of the frequency divider 186, a radio of an output frequency / input frequency of the DDS 14, a frequency division ratio M<SB>a</SB>of the frequency divider 12, and a number of multiple M<SB>b</SB>of the multiplier 13 are adjusted so that the transmission wave has the instructed frequency and a combination between the input signal frequency and the output signal frequency in the DDS 14 brings spurious radiation in an output of the DDS 14 to a prescribed level or below. <P>COPYRIGHT: (C)2007,JPO&INPIT |
