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SU-X902
m@ DIGITALIZATION OF AUDIO SIGNALS
MWhy digitize?
* Audio signals are analog signals with a continuous form.
* When these audio signals are subjected to repeated electronic
processing (recording, playback, etc.), they become noisy and
distortion occurs, thus resulting in deterioration of the sound
quality.
«When
these signals are first digitized before processing, they
have the foliowing advantages that prevent deterioration of the
sound quality:
@ Resistance to noise
® Extremety low distortion
® Fiat, even frequency response
Analog signals
Digital signals
a
i
>
Even if noise
occurs
SLU
Processed as uniform
series of Os and 1s,
without distortion.
NUL
+
Original sound
Recording to CD
Analog signals
XN
<>
CD play
Compact disc player
a>} Mb oo |—
Digital/analog conversion
Analog signals
—_—_—_—
Analogidigital conversion
TULL
Amplifier
ae
W How signals are digitized
If it is known to what degree of minuteness the human ear can
distinguish sounds, it is then possible, by using that data as the
standard reference, to digitize them by dividing analog signais
into minute pieces, after which they can be transmitted with a
high degree of precision, and thereafter
recorded and played
back in the digitized format.
Analog signals are sampled, quantified and encoded.
g
23
os
& &
Time
2
Sampling:
3 cy i
Analog signals are minutely sub-
as
divided on the lateral axis.
Es
qs
o
|}
Quantification:
3 ey
=
Sampled signals are minutely
é s
sub-divided on the vertical axis.
o
>
Digital signals
Recorded to CD
"il — =
Digital signals
Speaker systems
econ ee |
Sound deterioration may easily occur because analog signals are
sent to the amplifier through stereo connection cables.
Speaker systems
This method
mpact disc player
_—
Amplifier
Digital/anaiog conversion
+4
1]
Sound
deterioration
does
not easily occur
tecause
digital
signals are sent to the amplifier through optical-fiber cable.
(| What the sampling frequency is
)
The sampling frequency expresses the degree of minuteness to
which
signals can be cut, relative to a certain specified time
interval, during sampling.
For compact disc sound:
Analog signals are cut 44,100 times (i.e., 44.1 kHz) during one
second.
This 44.1 kHz is, therefore, the sampling frequency for compact
disc sound.
(| What analog/digital conversion is
)
Audio signals (analog signals) are taken out (sampled) at certain
fixed time intervals. The points at which this sampling frequency
occurs are digitally encoded and converted to digital signals.
What digital/analog conversion is
)
Each sampling frequency point is returned (converted) to voltage.
thus converting digital signais to the analog signais that we can
hear.
|
SU-X902
Removal of the Cabinet
Procedure
Ref. No.
1
1. Remove the 6 screws (@~ @)-.
2. Remove the cabinet in the direction of the arrow.
Removal of the Power Switch/Speaker
Select Switch P.C.B.
Ref. No.
3
Procedure
1-2-3
Power switch/Speaker select switch P.C.B
Remove the 2 screws (@, @).
Procedure
Ref. No.
2
Removal of the Front Panel Unit
12
J501
1. Remove the 2 connectors (J501, J502).
—Removal of the Connector—
\
Fiot cable
4
Connector
ef
2. Remove the 3 screws (@~®).
3. Remove the front panel unit in the direction of the arrow.
Ref. No.
4
Removal of FL Drive P.C.B.
Procedure
QO
i
1.
Remove the 4 knobs (@~@).
2. Remove the 4 nuts (@~ @)
J63IA
J632A
3. Remove the 3 screws (Q@~ @®).
4. Remove the 3 connectors (J631A, J632A. J633A)
i
L e n enn
eRe
NRaREA
Nee
Ne
ROE
TAR
AE an ot a
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