Sony PCM-D100 Operating Instructions Manual page 70

Settings menu items (continued)
Menu Item
Recording SBM(Super Bit
Settings Mapping)
Peak Hold
70
Settings (*: Default setting)
When LPCM 16bit REC Mode is selected, you can reduce noise using
the Super Bit Mapping function.
ON: The Super Bit Mapping function works to reduce noise.
OFF*: The Super Bit Mapping function is disabled.
Note
Super Bit Mapping significantly increases the dynamic range
ˎ ˎ
acoustically by reducing noise that is particularly easy to hear within the
band audible to humans. In order to improve the audio quality when
converting 20-bit data into 16 bits, the top 4 bits of information within
the lower data, which is usually discarded, is integrated into the 16-bit
data.
You can select whether the maximum value of the input signals
(peak value) is maintained.
Auto*: The peak value is not maintained and is reset periodically.
Manual: The peak value is maintained and displayed until you stop
recording or execute "Reset Peak Data."