| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a crystal oscillation circuit that is highly effective in suppressing higher order harmonics by adapting an output waveform not to generate harmonics. <P>SOLUTION: The crystal oscillation circuit includes: an oscillation circuit section whose oscillating source is a crystal oscillator; a plurality of stages of buffer circuit sections 11, 12, 13 each comprising an inverter of CMOS transistors whose input is an output signal of the oscillation circuit section; and a CMOS push-pull amplification circuit 14 for amplifying an output of the buffer circuit sections via capacitors CB1, CB2 for cutting DC components therefrom. Resistive elements R3, R4 are connected between a CMOS transistor Tp4 and a CMOS transistor Tn4 of the buffer circuit section 13, with a midpoint thereof being an output of the buffer circuit section 13. An output signal is thus waveform-shaped according to a time constant depending on the resistive elements and the capacitors. A memory has memory settings for allowing MOS switch means 17 to turn on/off a circuit 16 bypassing the resistive elements. <P>COPYRIGHT: (C)2013,JPO&INPIT |
