Freq. Trans.
It is necessary to set the note number when setting the signal frequency and cutoff frequency.
Inside the synthesizer, note numbers are converted to frequencies by a logarithmic function.
NoteNumber is specified in 2 bytes.
Normally, the lower byte is set to 0 and the higher byte is changed to operate in semitone steps.
The relationship between the higher byte value and the frequency is represented by the following Formula. 
Relationship between 2-byte Note Number value and frequency.
