220 Chapter 18—Digital I/O
03D—Owner’s Manual
Output Dither
The 03D’s AES/EBU connection outputs digital audio data with a wordlength of 24 bits.
The Coaxial connection outputs digital audio data with a wordlength of 20 bits. When
a high-resolution digital audio signal is transferred to a lower-resolution system, some
of the least-significant bits (LSB) are ignored by the receiving system. This can make
low-level signals sound grainy and step like, similar to the breakup produced by a
low-resolution digital reverb processor as a signal fades. The wordlength of a digital
audio signal must be shortened to match that supported by the receiving system. The
digital dither technique is used to optimize this process. The output of a special pseu-
dorandom number sequence generator is compared with the lowest bit of the short-
ened data word and those bits below it and is rounded either up or down prior to D/A
conversion, thereby optimizing the 03D digital output signals for use with lower-reso-
lution systems. Dither endows digital signals with a noise floor close to the minimum
theoretical limit. Whether or not you use dither really depends on your application. If
you’re unsure, it’s best t o use dither.
Dither can be set independently for the DIGITAL STEREO OUT and each pair of
YGDAI outputs. Set the WORD LENGTH parameters to mat ch the w o r dlength sup-
ported by the digital device connected to the DIGITAL STEREO OUT or YGD AI card.
If, for example, you have a 20-bit digital recorder connected to the 03D’ s DIGIT AL STE-
REO OUT for use as a master recorder, set the wordlength to 20 and turn on dither for
the ST OUT DIGITAL.
The ST OUT setting applies to the AES/EBU output and Coaxial output.
1. Use the [DIO] button to locate the Dither page shown below.
2. Use the cursor buttons to select the dither on/off and wordlength
switches, and the [ENTER] button to set them.
If you are using a mouse, simply click the switches.