Sharp CD-PC1881V Service Manual page 14

CD-PC1881V
EXPLANATION OF DOLBY SURROUND PRO LOGIC AND EVALUATION METHOD
Outline
• Namely, two speakers are connected in parallel to one
amplifier.
• In the Pro Logic BYPASS mode the amplifier for C-ch (center
channel) and the amplifier for S-ch (surround channel) are in
MUTE state. The SP output is cut.
• State of element output and terminal output in specific mode
State of set Dolby Pro Logic
Output point
IC501 12 pin L-out Output enabled state
11 pin R-out Output enabled state
IC501 9pin C-out No output
IC501 10pin S-out No output
SP OUT L-ch Output enabled state
(SO901) R-ch Output enabled state
SP OUT C-ch No output in MUTE (Q404) state
(SO901)
SP OUT S-ch No output in MUTE (Q403) state
(SO901)
Test tone output
• Pro Logic ON Normal mode
Press the remote control TEST TONE button.
→Output of only L-ch →Output of only C-ch
↑
Output of only S-ch ← Output of only R-ch
The test tone (noise) is repeatedly output for output period
(2 sec).
In this case the following indication appears repeatedly.
→TEST →L-ch →C-ch
↑
↓
S-ch ← R-ch
• Pro Logic ON Phantom mode
Press the remote control TEST TONE button.
→Output of only L-ch →Output of only R-ch
↑
← Output of only S-ch
The test tone (noise) is repeatedly output for output period
(2 sec).
In this case the following indication appears repeatedly.
→TEST → L-ch → R-ch
↑
↓
← S-ch←
Relation between VIDEO IN input and output in Pro Logic
ON state
(1) L-ch/R-ch same phase input into VIDEO IN input jack in
VIDEO Function mode
Output point
SP out L-ch Almost no output (only omitting component)
(SO901) R-ch Almost no output (only omitting component)
(SO901) SP out C-ch Input signal is output.
(SO901) SP out S-ch Almost no output (only omitting component)
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Dolby Pro Logic On mode
Bypass mode Normal mode
Output enabled state
Output enabled state
Output enabled state
Output enabled state
Output enabled state
Output enabled state
Output enabled state
Output enabled state
↓
↓
Normal mode
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• In the normal mode of Pro Logic ON mode the amplifiers for
C-ch and S-ch are in operative state, so that the SP output
appears.
• In the Phantom mode of Pro Logic ON mode the amplifier for
C-ch is in MUTE state, so that the SP output is cut. The
amplifier for S-ch (surround) is in operative state, so that the
SP output appears
Phantom mode
Output enabled state
Output enabled state
No output
Output enabled state
Output enabled state
Output enabled state
No output in MUTE (Q404) state
Output enabled state
Output point
SP out L-ch Input signal is output.
(SO901) R-ch Input signal is output.
(SO901) SP out C-ch SP cut, no output
(SO901) SP out S-ch Almost no output (only omitting component)
(2) L-ch/R-ch reverse phase input into VIDEO IN input jack in
VIDEO Function mode
(Reverse phase: Phase difference between L and R is 180°)
Output point
SP out L-ch Almost no output (only omitting component)
(SO901) R-ch Almost no output (only omitting component)
(SO901) SP out C-ch Almost no output (only omitting component)
(SO901) SP out S-ch Input signal is output.
Output point
SP out L-ch Almost no output (only omitting component)
(SO901) R-ch Almost no output (only omitting component)
(SO901) SP out C-ch SP cut, no output
(SO901) SP out S-ch Input signal is output.
• Accordingly, if you want to output signal waveform to C-ch SP
out, give the same phase input into L-ch/R-ch INPUT in the
Pro Logic Normal mode.
If one of channels receives input, C-ch does not output. Only
L-ch or R-ch outputs.
• If you want to output signal waveform to S-ch SP out, you can
use either Normal mode or Phantom mode. However, 180°
reverse phase input must be given to L-ch/R-ch INPUT.
Phantom mode
Normal mode
Phantom mode