ak4145 AKM Semiconductor, Inc., ak4145 Datasheet - Page 15

• Manufacturer Part Number: ak4145
• Description: Digital Stereo Btsc Encoder
• Manufacturer: AKM Semiconductor, Inc.

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The STR bit controls the Stereo/MONO output mode. Setting of the STR bit “1” (default) selects the BTSC stereo output
mode. Setting of the STR bit “0” selects the MONO mode. In parallel control mode, the AK4145 is fixed to the stereo
mode.
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The AK4145 includes the digital output volume control (DATT) for base band with 256 levels at linear step including
MUTE. This volume control is in front of the DAC and can attenuate the input data from 0dB to –42dB 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
■
When VCLK bit = “0”(default), the sync separator generates the sync signal using external composite video signal via the
CV27M pin. When VCLK bit = “1”, the 27MHz clock is required through this pin to generates the video sync signal. The
sync signal is used to generate the 15.734kHz pilot tone for the BTSC stereo encoding. In parallel control mode, this pin
is fixed to video sync input.
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The AK4145 has the stereo matrix control. The PL3-0 bits control the matrix.
Rev. 0.3
BTSC Stereo/MONO Output Control
Audio Composite Output Volume (DATT)
Video Sync Input
Stereo Matrix Control
PL3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
PL2
STR bit
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
1
0
PL1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
MONO mode, outputs only (L+R) component.
Stereo mode. outputs BTSC stereo composite
PL0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Table 10. DATT Transition Time
Table 12. Stereo/MONO Control
4LRCK
Table 13. Stereo Matrix Control
1 Level
DATT Transition Time
Composite audio output
Lch Output
(L+R)/2
(L+R)/2
(L+R)/2
(L+R)/2
MUTE
MUTE
MUTE
MUTE
Table
R
R
R
R
L
L
L
L
- 15 -
10. In parallel control mode, this volume is fixed to 0dB.
1020LRCK
255 to 0
Rch Output
(L+R)/2
(L+R)/2
(L+R)/2
(L+R)/2
MUTE
MUTE
MUTE
MUTE
R
L
R
L
R
L
R
L
(default)
REVERSE
STEREO
MONO
MUTE
Note
[AK4145]
2007/11