| 摘要 |
A tuning device for musical instruments including a high frequency oscillator having frequency controlled by a tone select switch and an octave select switch and the output SH of which is supplied to the input of an AND-gate, the output of which is supplied to the display device for the tone pitch and the other input of which is connected to the output of a reference time signal generator which comprises a flip-flop for a wait signal SW and which is started by the amplitude of the tone via a microphone, an amplifier, a filter, a smoothing device and a Schmitt-trigger, and which is stopped after the counting of a definite number of tone oscillations filtered and converted into rectangular pulses. The opening time of the gate is preset by external oscillation with an internal oscillation, the frequency of which is started depending upon the frequency of the tone to be measured. The constant measuring accuracy being independent from the tone and enabling also a tuning deviating from standard pitch are features provided as advantages along with a further advantage of short measuring time with good accuracy which is inherent to the period measuring method being additionally gained.
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