抄録
With the synchronous trigger of the reference frequency ƒ_s Hz suitable to a stretched scale, the observed fundamental wave of the piano sound moves at the rate of the deviation frequency on the CRT screen. The direction of the movement gives that of the pin rotation for tuning and the velocity of movement also does the tuning angle. The result of the pitch deviation with decision time of 0. 2 second represents that the lower limit of a deviation δ (cent) in the bass section is inversely proportional to ƒ^2_s and the upper limit in the treble section is inversely proportional to ƒ_s. Therefore;1) In the bass section the CRT tuning method is better used in the frequency range above 110 Hz where the resolution is high and observed with multiples of a detected fundamental wave. 2)In the treble section this method is better applied in the frequency range below 261. 6 Hz where the observable upper limit of deviation is 50 cent, and observed through a frequency divider. Consequently a trial tuning device for practical use is set up and satisfactory results are obtained.
