QS7785 NPC [Nippon Precision Circuits Inc], QS7785 Datasheet - Page 8

• Manufacturer Part Number: QS7785
• Description: 3D 2/4-Channel Stereo Surround Synthesizer
• Manufacturer: NPC [Nippon Precision Circuits Inc]

FUNCTIONAL DESCRIPTION
Operating Modes
The QS7785PF/CF operating mode can be con-
trolled over either a parallel interface (P/S = HIGH)
or one of two serial interfaces (P/S = LOW). The
Output mode
1. – (dash) = no output signal.
Output signal description
Mono signals should be input on both LIN and RIN.
In output mode 1, the output signal is a mixed signal
comprising the front-channel Qsurround processed
signal and the input stereo signal, that is output on
the 2-channel front speakers only.
In output mode 2, the signal path is the same as in
output mode 1, but the surround effect is enhanced
by increasing the component of the Qsurround pro-
cessed signal and reducing the component of the
input stereo signal.
In output modes 3 and 4, both the front speakers and
surround speakers are used to form a 4-channel sys-
Stereo Q
Stereo Q+
Stereo Q1
Mono → Stereo Q
Mono → Stereo Q+
Stereo bypass
× = indicates don’t care.
1 = HIGH, 0 = LOW
No.
10
11
12
1
2
3
4
5
6
7
8
9
Output signal
Input signals
Stereo/Mono
Stereo only
Stereo only
Mono only
Mixed front-channel Qsurround processed signal and input stereo signal output
Same as Stereo Q with increased Qsurround signal component and reduced input stereo signal component.
Mixed surround-channel Qsurround processed signal and input stereo signal output.
Mono signal converted to virtual stereo signal, and then processed in the same way as Stereo Q signals.
Mono signal converted to virtual stereo signal, and then processed in the same way as Stereo Q+ signals.
Input stereo signal is output as-is without processing.
BYP
0
0
0
0
0
0
0
0
1
1
1
1
Control pins/SDA signal
MONO
0
0
0
0
1
1
1
1
0
0
1
1
QS7785PF/CF
SUR
0
0
1
1
0
0
1
1
0
1
0
1
operating mode, control pins and SDA signal rela-
tionship is shown in the table below. Refer to “Serial
Interface Timing” for the SDA signal format.
tem for a rich surround space. The front-channel sig-
nal is the same as in output modes 1 and 2. The
surround-channel signal is a mixed signal compris-
ing an enhanced surround effect Qsurround pro-
cessed signal and the input stereo signal.
In output modes 5 to 8, the input signal is a mono
signal. The mono signal is first converted to a virtual
stereo signal and then processed in the same way as
in output modes 1 to 4, respectively. In modes 5 and
6, the surround signal is output on 2-channel front
speakers only. In modes 7 and 8, the surround signals
are output on 4-channel front and surround speakers.
SP
×
×
×
×
0
1
0
1
0
1
0
1
Description
Mono → Stereo Q+
Mono → Stereo Q+
Mono → Stereo Q
Mono → Stereo Q
FROUT/FLOUT
Stereo bypass
Stereo bypass
Stereo bypass
Stereo Q+
Stereo Q+
Stereo Q
Stereo Q
–
NIPPON PRECISION CIRCUITS—8
Output signals
Mono → Stereo Q1
Mono → Stereo Q1
1
SROUT/SLOUT
Stereo bypass
Stereo bypass
Stereo Q1
Stereo Q1
Stereo Q1
–
–
–
–
–