input signal value increases, the output frequency starts changing if the
height becomes equivalent to 3/4 of the quantizing value. From then on,
the output frequency increases according to the quantizing value. On
the other hand, when the input signal decrease, the output frequency
starts decreasing if the height becomes equivalent to 1/4 of the
quantizing value.
Although the noise can be reduced using the low-pass filter (In.07), the
response on the input signal takes long as the set value gets higher.
Since it becomes difficult to control the frequency if the input signal is
delayed, a period of long pulse (ripple) may occur on the output
frequency.