| 摘要 |
PURPOSE:To perform tuning without irregularity, by starting measurement in synchronous relation to a musical sound signal after the musical sound signal is delayed for a definite time from automatic starting in becoming stable and stopping measurement when the signal is not inputted for a definite time or more. CONSTITUTION:A wave form shaping circuit 23 converts at least a receiving musical sound signal to a rectangular wave. A first counter circuit 30 counts a definite number of the rectangular waves and a second counter circuit 32 counts a reference clock during a time when the circuit 30 is counting the rectangular waves. A decoder circuit 34 converting the output of the circuit 32 to a proper shape, an automatic start circuit 26, a delay circuit 27, an automatic stop circuit 31 and a timing circuit 28 are provided and the counting of the rectangular wave is started in synchronous relation to the reference clock so as to delay a definite time after the input musical sound signal reaches a set level and the reference clock is counted only for a period counting a definite number of rectangular waves while the result is converted by the circuit 34 and the tuning of musical sound is performed to enable automatic measurement by simple operation. |
