| 摘要 |
PURPOSE:To improve a keying ratio by forming an MOSFET in a keying circuit having an MOSFET outputting amplitude of an input signal by controlling said amplitude on the basis of a controlling signal in a self alignment process. CONSTITUTION:When an MOSFET is formed which is used for a keying circuit in an electronic musical instrument and the like outputting a musical scale signal by controlling amplitude of an input signal on te basis of an envelope controlling signal, the MOSFET is formed on a semiconductor substrate by using a self alignment process utilizing an Si gate 5. Hereby, since stray capacity between a and a source and the like of the MOSFET can be reduced, and a keying ratio can be considerably improved. |
