Yamaha O2R Manual Do Utilizador

Digital I/O, Setup, and Utilities

When you connect a number of digital audio devices together, you may 
find their digital word size is different. For example, the 02R uses a 20-bit 
word size for input and output and a 32-bit word size for internal 
processing. Professional digital equipment uses a 24-bit wordsize, while 
consumer digital equipment uses a 20-bit wordsize. In order to obtain the 
best possible signal quality, the 02R has a dither function for its internal bus 
and stereo bus outputs.

Dithering is a mathematical process where a random noise is added to the 
least significant bit of a digital word. With very low level signals, the 
quantization error becomes correlated to the signal level. This creates a 
small but measurable amount of distortion. By adding dither, the 
correlation between the signal level and the quantization error is cancelled, 
allowing the digital system to encode amplitudes smaller than the least 
significant bit. If you change the word size as a signal passes from one 
digital system to another, being able to add dither allows you to maintain a 
high quality signal.

Shown below is the DIGITAL I/O 4/5 page—Dither.

You can turn the dither function on or off for the stereo bus and for the 
internal buses 1 through 8. The internal buses are paired for the dither 
function.

You can add dither to compensate for any word size from 16-bit to 24-bit.