| 摘要 |
PROBLEM TO BE SOLVED: To generate a ringer signal capable of allowing sounding an analog telephone that cannot be sounded by a rectangular wave ringer signal with a simple configuration. SOLUTION: In the analog telephone 17 that cannot be sounded by the rectangular wave ringer signal generated from an output terminal 162 at a switching power supply 100, a waveform formation section 200 comprising a capacitor C4 and a resistor R6 is installed at the output side of the switching power supply 100, thus weakening the rectangular wave ringer signal and sounding the analog telephone 17 by reducing a harmonic content in the ringer signal. COPYRIGHT: (C)2005,JPO&NCIPI
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