ASAHI KASEI

[AK4385]

MS0246-E-01

2006/01

- 12 -

De-emphasis Filter

A digital de-emphasis filter is available for 32, 44.1 or 48kHz sampling rates (tc = 50/15µs) and is enabled or disabled

with DEM0 and DEM1. In case of double speed and quad speed mode, the digital de-emphasis filter is always off.

DEM1

DEM0

Mode

0

0

44.1kHz

0

1

OFF

Default

1

0

48kHz

1

1

32kHz

Table 8. De-emphasis Filter Control (Normal Speed Mode)

Output Volume

The AK4385 includes channel independent digital output volumes (ATT) with 256 levels at linear step including MUTE.

These volumes are in front of the DAC and can attenuate the input data from 0dB to –48dB and mute. When changing

levels, transitions are executed via soft changes; thus no switching noise occurs during these transitions. The transition

time of 1 level and all 256 levels is shown in Table 9.

Transition Time

Sampling Speed

1 Level

255 to 0

Normal Speed Mode

4LRCK

1020LRCK

Double Speed Mode

8LRCK

2040LRCK

Quad Speed Mode

16LRCK

4080LRCK

Table 9. ATT Transition Time