| 摘要 |
PROBLEM TO BE SOLVED: To provide a mobile phone capable of reducing high frequency noise leaking from a logic circuit such as a CPU or a DSP to a wireless transmission/reception section. SOLUTION: A TCXO 20 outputs a highly stable reference frequency signal. A PLL-A11 receives the reference frequency signal and outputs a first clock signal synchronized with the reference frequency signal. A PLL-B12 receives the reference frequency signal and outputs a second clock signal whose frequency varies periodically with respect to the reference frequency signal. A peripheral circuit A13 includes a function circuit whose frequency specifications are decided such as an Ir communication control circuit and receives the first clock signal with a prescribed period. A peripheral circuit B14 is configured to include the logic circuit such as the CPU or the DSP and is operated by the second clock signal whereby the power density of harmonic noise at a particular frequency can be lowered because no specifications of the frequency precision exist. COPYRIGHT: (C)2005,JPO&NCIPI
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