| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem such as frequency deviation or period jitter deterioration caused by influences of power supply noise of a logic circuit, in a reference frequency generating circuit. <P>SOLUTION: A power source for the logic circuit 12 such as a CPU or a peripheral circuit is supplied from a regulator 13, and for a power source for the reference frequency generating circuit 11, high frequency noise of the power source is supplied via a low-pass filter 10 having an attenuation amount equal to or more than 10 dB. Thus, the frequency deviation or the jitter deterioration caused by high frequency noise generated in the logic circuit 12 can be suppressed and communication can be performed by connecting a reference frequency to a UART serial circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT |
