VOLUME ADJUSTER FOR SOUND GENERATING DEVICE |
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| 申请号 | EP00951917 | 申请日 | 2000-08-09 | 公开(公告)号 | EP1137172A4 | 公开(公告)日 | 2005-03-09 |
| 申请人 | MATSUSHITA ELECTRIC IND CO LTD; | 发明人 | INOUE MASAYUKI; GOMI MIKA; ISHIHARA TAKASHI; | ||||
| 摘要 | A volume adjuster for a sound generating device for changing the volume in multiple steps, made upper of a small number of parts. The volume adjuster comprises a sound generating unit (13), two resistors (Ra, Rb) connected in series with a drive circuit of the sound generating unit (13), two switch sections (SW1, SW2) connected, respectively, in parallel with the resistors (Ra, Rb), a control section (11) for turning the switch sections (SW1, SW2) on/off with control signals (C1, C2), an NPN transistor (Qf) connected in series with the sound generating unit (13), and a sound pattern generator (15) for turning the NPN transistor (Qf) on/off with a sound pattern signal (f) wherein the volume of the sound generated by the sound generating unit (13) is regulated stepwise by turning the switch sections (SW1, SW2) on/off with the control signals (C1, C2) thereby selecting the resistance of a resister connected with the sound generating unit (13) variably. | ||||||
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