SSM-2005 Analog Devices, SSM-2005 Datasheet - Page 11

• Manufacturer Part Number: SSM-2005
• Description: Search ---> SSM2005
• Manufacturer: Analog Devices

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TYPICAL OUTPUTS IN VARIOUS MODES
The SSM2005 Circle Surround decoder uses ambiance and
directional information already present in a stereo signal, and
does not require the audio signal to be encoded. The device
requires no delay generators or noise reduction. Fully differenti-
ated rear channels provide rear stereo separation for enhanced
spatial perception, a feature unique to Circle Surround.
Video mode provides the highest degree of channel separation
between the front and center speakers. Video mode cancels com-
mon center channel material from the left and right front chan-
nels. This restores a wide stereo image to matrix encoded sound
tracks, while maintaining a solid center channel for dialogue and
mono information.
The Music mode is optimized for unencoded stereo music repro-
duction, with full bandwidth on all channels. The steering for the
LF and RF channels is deactivated to prevent any stereo image
wandering. The independent two-band rear channel steering
provides excellent surround imaging, even in car audio applica-
tions. Well balanced sound is obtained everywhere within a 4- or
5-speaker setup.
The 5.2.5 mode provides the maximum channel separation to
the surround channels, and should be used with any encoded
stereo input signal. The 4.2.4 mode can be used to reduce the
dynamic steering of the surround channels, allowing the
SSM2005 to simulate a 4-channel surround sound decoder.
Sound Spread OFF allows the maximum channel separation
between the surround and front speakers. With Sound Spread
OFF, a hard panned left input signal will produce an output
only in the left front output. In Sound Spread ON mode, a hard
panned left input signal will produce equal output from the left
front and left surround outputs.
The following tables demonstrate the differences between the
modes of the SSM2005 under various input conditions. The L
and R
differences in magnitude (in dB) and phase (in degrees). For
example, a 0
tude, but opposite in phase to R
Input
|L
dB
0
0
L
R
–6
–6
REV. 0
T
T
T
Only
Only
| – |R
0
180
Table V. Video/5.2.5/Sound Spread OFF/Center ON
0
180
T
inputs are at 2 kHz, and are shown in terms of their
T
|
180 input means L
Output
(dB)
|LF|
– 30
–35
0
–60
0
–30
|RF|
–30
–35
–60
0
–15
–36
T
.
T
is exactly equal in magni-
|C|
+6
–45
–30
–30
–4
–26
|LS|
–40
+6
–30
–35
–25
0
|RS|
–40
+6
–35
–30
–30
–15
T
–11–
Input
|L
dB
0
0
L
R
–6
–6
Input
|L
dB
0
0
L
R
–6
–6
Input
|L
dB
0
0
L
R
–6
–6
Input
|L
dB
0
0
L
R
–6
–6
T
T
T
T
T
T
T
T
Table VIII. Video/5.2.5/Sound Spread ON/Phantom Center
T
T
T
T
Only
Only
Only
Only
Only
Only
Only
Only
| – |R
| – |R
| – |R
| – |R
0
180
0
180
0
180
0
180
Table VII. Music/5.2.5/Sound Spread ON/Center ON
Table IX. Video/4.2.4/Sound Spread OFF/Center ON
Table VI. Video/5.2.5/Sound Spread ON/Center ON
0
180
0
180
0
180
0
180
T
T
T
T
|
|
|
|
Output
(dB)
|LF|
– 30
–35
0
–60
0
–30
Output
(dB)
|LF|
0
0
0
–60
0
0
Output
(dB)
|LF|
+3
–35
0
–60
0
–30
Output
(dB)
|LF|
– 30
–35
0
–60
0
–30
|RF|
–30
–35
–60
0
–15
–36
|RF|
0
0
–60
0
–6
–6
|RF|
+3
–35
–60
0
–15
–36
|RF|
–30
–35
–60
0
–15
–36
|C|
+6
–45
–30
–30
–4
–26
|C|
+2
–45
–30
–30
–4
–26
|C|
Off
Off
Off
Off
Off
Off
|C|
+6
–45
–30
–30
–4
–26
SSM2005
|LS|
–40
+6
0
–30
0
0
|LS|
–40
+6
0
–30
0
0
|LS|
–40
+6
0
–30
0
0
|LS|
–40
+6
–32
–32
–26
0
|RS|
–40
+6
–30
0
–25
–15
|RS|
–40
+6
–30
0
–25
–15
|RS|
–40
+6
–30
0
–25
–15
|RS|
–40
+6
–32
–32
–26
–2