Sharp SM-SX100 User manual

SM-SX100
– 1 –
SM-SX100
• In the interests of user-safety the set should be restored to its
original condition and only parts identical to those specified be
used.
SERVICEMANUAL
SHARP CORPORATION
No. S3021SMSX100/
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.
CONTENTS Page
IMPORTANT SERVICE NOTES (FOR U.S.A. ONLY)........................................................................................................2
IMPORTANT SERVICE NOTES (FOR U.K. ONLY) ...........................................................................................................2
SPECIFICATIONS ............................................................................................................................................................. 3
NAMES OF PARTS ........................................................................................................................................................... 3
OPERATION MANUAL ...................................................................................................................................................... 6
DISASSEMBLY.................................................................................................................................................................. 7
ADJUSTMENT ................................................................................................................................................................. 10
INTRODUCTION OF CIRCUIT OUTLINE ....................................................................................................................... 12
EXPLANATION OF 1-BIT UNIT....................................................................................................................................... 18
WIRING PROCESS DIAGRAM ....................................................................................................................................... 21
BLOCK DIAGRAM ........................................................................................................................................................... 24
NOTES ON SCHEMATIC DIAGRAM .............................................................................................................................. 26
TYPE OF TRANSISTOR AND DIODE............................................................................................................................. 26
SCHEMATIC DIAGRAM/WIRING SIDE OF P.W.BOARD............................................................................................... 27
WAVEFORMS OF CD CIRCUIT...................................................................................................................................... 50
TROUBLESHOOTING ..................................................................................................................................................... 51
FUNCTION TABLE OF IC................................................................................................................................................ 55
PARTS GUIDE/EXPLODED VIEW/PACKING METHOD (FOR U. K. ONLY)/PACKING OF THE SET (FOR U.S.A. ONLY)

SM-SX100
– 2 –
FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT, PLEASE REFER
TO THE OPERATION MANUAL.
IMPORTANT SERVICE NOTES (FOR U.K. ONLY)
Beforereturningtheunittothecustomeraftercompletionofa
repairor adjustmentitis necessaryforthe followingwithstand
voltage test to be applied to ensure the unit is safe for the
customer to use.
Setting of Withstanding Voltage Tester and set.
Set name set value
Withstanding Voltage Tester
Test voltage 2,120 VPEAK
1,500 VRMS
Set time 60 secs
Set current(Cutoff current) 4 mA
Unit
Judgment
OK: The “GOOD” lamp lights.
NG: The “NG” lamp lights and the buzzor sounds.
SHORT-CIRCUIT
AC POWER
SUPPLY CORD
CONNECT THE PROBE
TO GND OF CHASSIS
SCREW
PROBE
AC
UNIT
WITHSTANDING
VOLTAGE TESTER
+
-
OUT
IMPORTANT SERVICE NOTES (FOR U.S.A. ONLY)
BEFORE RETURNING THE AUDIO PRODUCT
(Fire & Shock Hazard)
Before returning the audio product to the user, perform the
following safety checks.
1. Inspect all lead dress to make certain that leads are not
pinchedorthathardwareisnotlodgedbetweenthechassis
and other metal parts in the audio product.
2. Inspect all protective devices such as insulating materials,
cabinet,terminalboard,adjustmentandcompartmentcovers
or shields, mechanical insulators etc.
3. To be sure that no shock hazard exists, check for leakage
current in the following manner.
* Plug the AC line cord directly into a 120 volt AC outlet.
* Using two clip leads, connect a 1.5k ohm, 10 watt resistor
paralleled by a 0.15µF capacitor in series with all exposed
metal cabinet parts and a known earth ground, such as
conduit or electrical ground connected to earth ground.
* Use a VTVM or VOM with 1000 ohm per volt, or higher,
sensitivity to measure the AC voltage drop across the
resistor (See diagram).
* Connect the resistor connection to all exposed metal parts
havingareturnpathtothechassis(antenna,metalcabinet,
screw heads, knobs and control shafts, escutcheon, etc.)
and measure the AC voltage drop across the resistor.
AllcheckmustberepeatedwiththeAClinecordplugconnection
reversed.
Anyreading of0.3voltRMS(this correspondsto0.2milliamp.
AC.) or more is excessive and indicates a potential shock
hazard which must be corrected before returning the audio
product to the owner.
TO EXPOSED
METAL PARTS
CONNECT TO
KNOWN EARTH
GROUND
TEST PROBE
0.15 µF
1.5k ohms
10W
VTVM
AC SCALE

SM-SX100
– 3 –
Specifications for this model are subject to change without
prior notice.
SPECIFICATIONS
120 V, 60 Hz
230 V, 50 Hz
220 - 240 V, 50/60 Hz
230V, 50 Hz
220 V, 50 Hz
110 - 120 V, 50/60 Hz
220 - 240 V, 50/60 Hz
Rated output power:
RMS; 100 W + 100 W (DIN 45 500)
Total harmonic distortion:
0.02 % (1 kHz, 1 W)
Frequency response:
5 Hz-20 kHz (+1dB, -1dB)
5 Hz-100 kHz (+1dB, -3dB)
Dynamic range:
105 dB (5 Hz-20 kHz)
A/D noise shaping:
7th-order (delta-sigma) modulation
Input terminals:
DIGITAL1; ST link optical
DIGITAL2; BNC coaxial
DIGITAL3; RCA coaxial
DIGITAL4; Square type optical
SACD; RCA analog, 1 BIT digital
LINE 1; RCA analog
(350 mV rms / 50 k ohms)
LINE 2; XLR analog balanced
(350 mV rms / 50 k ohms)
Output terminals:
DIGITAL OUT; Square type optical
LINE OUT; RCA analog
SPEAKERS; 8 ohms/4 ohms selectable
Power source/power consumption:
North America
Europe
Australia,
New Zealand
Singapore
Hong Kong
Other countries
76 W
70 W
70 W
70 W
72 W
70 W
70 W
POWER
CONSUMPTION
Dimensions:
Width; 472 mm (18 - 5/8”)
Height; 89 mm (3 - 1/2”)
Depth; 462 mm (18 - 3/16”)
Weight: Approx. 18.5 kg (40.8 lbs.)
POWER SOURCE
NAMES OF PARTS
1234
1 Power button
Turns the unit on or off.
2 Volume control knob
Controls the sound level.
3 Volume display
Displays the sound level within the range
of “0” - “128”.
4 Input selector buttons
Used to select the equipment source you
want to play back.
When the power is turned on, the unit is
switched to “SACD”.
To cut the output to the speaker with
the power turned on:
Set the sound level at “0” then press and
hold the corresponding input selector but-
ton for 2 seconds or more.
The signal output to the speaker returns
when you reset the sound level at “1” or
higher.
Front Panel

SM-SX100
– 4 –
8 Digital output terminal (OPT)
Connect equipment using a square type
optical digital cable.
9 Line output terminals
Connect equipment using RCA cords.
6 Line 1 input terminals
Connect equipment using RCA cords.
7 Line2 inputterminals (BALANCED)
Connect equipment using XLR cables.
2.COLD(–)
3.HOT(+)
1.GND
BALANCED terminal:
The balanced output terminal pins 2.COLD (-)
and3.HOT(+)arereversedonsomeequipment,
suchas a CD player. If you connectsuch equip-
ment to this product using XLR cables, the sig-
nals are in antiphase. In this case, change the
pins 2 and 3 of one connector of the XLR cable
to match them to the equipment that you are
connecting. See diagram below.
8
67
9
CD player etc. This product
These terminals send signals of the exter-
nal equipment connected to the RCA (of
SACD), LINE 1 or LINE 2 terminals.
This terminal send signals of the external
equipment connected to the DIGITAL 1, 2 ,
3 or 4 terminal.
12
3
12
3
GND
COLD
HOT
GND
COLD
HOT
1 Digital 1 input terminal (ST) *
Connect equipment using ST link optical
digital cable.
5 SACD/1-bit signal input terminals
Connect the super audio CD player using
RCA cords or the 1-bit signal cable included
with your Sharp SACD player.
When both the RCA cords and the 1-bit sig-
nal cable are connected, signals from the
latter have priority.
When nothing is connected to the 1 BIT in-
put terminal, signals from the RCA cords
are used.
(If you use the 1 BIT input terminal, refer to
the operation manual for equipment which
has a 1-bit signal output terminal.)
3 Digital 3 input terminal (COAX) *
Connect equipment using RCA coaxial
cable.
4 Digital 4 input terminal (OPT) *
Connect equipment using the square type
optical digital cable.
2 Digital 2 input terminal (BNC) *
Connect equipment using BNC coaxial
cable.
*For digital input to this product, use
equipment which adapts to the digital
audio interface.
(32kHz, 44.1kHz, 48kHz)
4
1235
Rear Panal

SM-SX100
– 5 –
10 Speaker output terminals
(compatible to bi-wiring)
Speaker output terminals of the RIGHT and
the LEFT channels are located above and
below each other in two rows for speaker
bi-wiring.
Since the upper and lower rows have com-
mon specifications, you can connect your
speakers to either row when using a conven-
tionalspeakersystem. When connecting a bi-
wired compatible speaker system, the upper
row is used for the high frequency speaker
drivers, and the lower row is used for the low
frequency speaker drivers.
12 AC input socket
Connect the power cord to an AC INPUT
socket.
Plug the speaker cord in firmly and be care-
ful that the end of the cord does not touch
the next terminal or speaker cord, as this
could cause damage to the amplifier.
Use a speaker system which has 100 W
or more rated power input and 4 ohms -
8 ohms impedance.
Note for users in areas other than North
America:
When connecting the speaker cord, wind it
firmly around the terminal as shown in the il-
lustration below.
11 Impedance selector
This amplifier is designed to operate with a
variety of speaker systems. Set the imped-
ance selector switch to the proper setting
depending on your speaker system’s im-
pedance.
Switch to 4 OHMS if the impedance of the
speaker system is 4 - 6 ohms, to 8 OHMS
if it is 8 ohms .
(4 - 6 ohms)
(8 ohms)
10
11 12
Note:
Be sure to turn the amplifier power off when
changing the impedance selector switch
position. Failure to turn the power off may
cause damage to your speakers.
Speaker cord
(High frequencies)
(Low frequencies)
Speaker cord

SM-SX100
– 6 –
OPERATION MANUAL
Speakers
7th-order
(delta-sigma)
modulator
1-bit coding LSI
Fixed-voltage
high-speed
switching circuit Low-pass
filter network
1-bit
control
signals
Power
amplifier
switching
signal Out-
put
Fixed voltage
Analog signal
Multi-bit digital signal
(32kHz, 44.1kHz, 48kHz)
1-bit signal
Over-
sampling
Direct input
(delta-sigma) dynamic feedback
This product uses 1-bit signals as control signals.As a result, amplification which maintains a
1-bit signal performance is realized by switching the fixed-voltage power with precise quartz-
crystal accuracy.
Adopting the concept of “ (delta-sigma) Dynamic Feedback”, this product enables stable am-
plification faithful to the original sound by sending back the power voltage fluctuations (which
affects the audio signal) to the “7th-order (delta-sigma) modulator 1-bit coding LSI” which
corrects the 1-bit control signal in real time.
Samplingthe input signal ata high-frequency approx. 2.8MHz(64fs), the (delta-sigma) modu-
lation circuit yields a 1-bit signal stream which faithfully reproduces the original sound.
In this 7-th order (delta-sigma) modulation block, the quantization noise is shifted to higher
range to generate 1-bit signals which secure high signal to noise ratio in the playback band.
Using these 1-bit signals as control signals, the fixed-voltage high-speed switching circuit is con-
trolled. The signals abstracted from the switching circuit are sent to the low-pass filter network and
used to drive speakers.
This amplifier has no analog amplifier elements and can obtain speaker driving power by “creating
1-bit control signals through high-speed sampling” and “synchronized high-speed switching to the
sampling frequency”. In consequence, amplification with excellent movement and transient char-
acteristics is fulfilled.
1 bit amplification process
Connecting the AC power cord
Power supply voltage:
Thevoltageusedbythisproductvaries,depend-
ing on the shipping destination. Check if the
voltage written on the rear panel of the unit is
suitable for that of your country.
Notes:
Plug the AC power cord into a convenient
AC socket, after any connections.
Unplug the AC power cord from the AC
socket if the unit will not be in use for a
prolonged period of time.
Never use a power cord other than the one
supplied. Use of a power cord other than
the one supplied may cause an electric
shock or fire.
AC Plug Adaptor:
In areas (or countries) where an AC socket
as shown in illustration
2
is used, connect
the unit using the AC plug adaptor supplied
with the unit, as illustrated. TheAC plug adap-
tor is not included in areas where theAC wall
socket and AC power plug can be directly
connected (see illustration
1
).
Note for users in Australia and New
Zealand:
AnAC plug adaptor is not supplied if the cord
has an Australian Standard plug.
1
2
NOTES FOR USE
To AC INPUT
To an AC socket
Speaker cord connection
Be sure that the power is turned OFF when
connecting the speaker cord. Failure to
turn the power off can result in a short cir-
cuit that will place the amplifier into the
protection circuit mode and cause the
amplifier to shut down. If this occurs, make
sure that the amplifier is off, then discon-
nect the power cord from the socket to re-
set the circuit breaker. You can then re-
connect the cord to use the amplifier.
Volume setting
Make sure to set the volume to the mini-
mum sound level before turning on the
amplifier power or performing any input
switching. Failure to do this may result in
damage to your speaker system.
The supply voltage of the switching circuit
is not linked with volume adjustment.
Therefore, a constant voltage is supplied
even if not playing back sound and residual
sound may be generated slightly such as
when the volume is turned up. This is nor-
mal.
If a problem occurs
If this product is subjected to strong exter-
nal interference (excessive shock, static
electricity, abnormal supply voltage due to
lightning, etc.) or if it is operated incor-
rectly, it may malfunction.
In such a case, turn the power off.
Turn the power on again and check that the
product works normally.
(If problems still occur, contact the dealer.)

SM-SX100
– 7 –
DISASSEMBLY
Caution on Disassembly
Follow the below-mentioned notes when disassembling
the unit and reassembling it, to keep it safe and ensure
excellent performance:
1. Be sure to remove the power supply plug from the wall
outlet before starting to disassemble the unit.
2.Takeoffnylonbandsorwireholderswhere they need to
beremovedwhendisassemblingtheunit.Afterservicing
theunit,besuretorearrangetheleadswheretheywere
before disassembling.
3. Take sufficient care on static electricity of integrated
circuits and other circuits when servicing.
Figure 7-2
Figure 7-1
Figure 7-3
1 Top Panel B 1. Hexagon Screw
(2.5mm) .................(A1) x2 7-1
2 Top Panel A 1. Hexagon Screw
(2.5mm) .................(B1) x6 7-1
3 Side Panel, Sub 1. Screw .................... (C1) x4 7-1
(Left/Right)
4 Side Panel 1. Screw .................. (D1) x18 7-1, 7-2
(Left/Right)
5
Connect Bracket B
1. Screw .....................(E1) x2 7-2
6
Connect Bracket A
1. Screw ................... (F1) x12 7-3
7 Shield Cover A 1. Screw .................. (G1) x14 7-3, 8-1
8 Shield Cover B 1. Screw .................. (H1) x12 8-1
9 Shield Cover C 1. Screw ..................... (J1) x7 8-1
10 Rear Panel 1. Screw ...................(K1) x14 7-3
2. Socket ....................(K2) x4
3. Soldering ................(K3) x4 8-5
11 Digital PWB 1. Screw ..................... (L1) x5 8-2
2. Socket .................... (L2) x5
12 Main PWB/Power 1. Screw .................. (M1) x10 8-2
Support PWB 2. Hexagon Specer ... (M2) x5
3. Socket ................... (M3) x8 8-2, 8-5
13 Relay PWB 1. Screw .................... (N1) x3 8-2
14 Power Filter PWB 1. Screw .....................(P1) x6 8-2
2. Socket ....................(P2) x2
15 Main Volume 1. Screw .................... (Q1) x6 8-2
PWB (Note 1) 2. Hexagon Screw
(1.5mm) ................ (Q2) x2
3. Nut ......................... (Q3) x1
16
Power Heat Cover 1.
Hexagon Screw
(Note 1) (1.5mm) ................ (R1) x2 8-3
2. Screw .................... (R2) x8
17 Power Switch 1. Screw ...................(S1) x16 8-3
PWB/Power PWB
18 Bottom Panel 1. Screw ................... (T1) x13 8-4
19 1Bit Amp PWB 1. Screw .................... (U1) x8 8-5
20 Front Panel 1. Screw .....................(V1) x6 8-6
21 LED PWB 1. Screw ....................(W1) x4 8-7
2. Socket ...................(W2) x1
22 Display Volume 1. Screw .....................(X1) x1 8-7
PWB (Note 1) 2. Knob .......................(X2) x1
3. Nut ..........................(X3) x1
4. Socket ....................(X4) x1
23 Front Panel 1. Screw .................... (Y1) 12 8-7
Bracket
24 Switch1 PWB/ 1. Screw ................... (Z1) x13 8-7
System Micro-
conputer PWB
REMOVAL PROCEDURE
STEP FIGURE
(D1)x3
ø3x8mm
(D1)x3
ø3x8mm
(C1)x4
ø3x14mm
(A1)x2
ø4x12mm
(B1)x6
ø4x12mm
Front Panel
Top Panel A
Top Panel B
Side Panel
(Left) Side Panel
Sub (Left)
Side Panel
(Right)
Side Panel
Sub (Right)
Rear Panel
Front
Panel
Connect
Bracket B
Side Panel
(Left)
Side Panel
(Right)
Rear Panel
(E1)x2
ø3x6mm (D1)x2
ø3x6mm
(D1)x2
ø3x6mm
(D1)x4
ø3x10mm
(D1)x4
ø3x10mm
Connect
Bracket A
Connect
Bracket A
Front
Panel
Rear Panel
(F1)x2
ø3x6mm
(F1)x2
ø3x6mm
(G1)x2
ø3x25mm
(G1)x2
ø3x20mm
(F1)x4
ø3x6mm
(F1)x4
ø3x6mm
(K1)x1
ø3x6mm
(K1)x4
ø3x6mm (K1)x2
ø3x10mm
(K1)x5
ø3x6mm
(K1)x2
ø3x6mm
Shield
Cover A

SM-SX100
– 8 –
(L1)x5
ø3x6mm
(L2)x3
(M3)x3
(L2)x2
Main PWB
Digital PWB
Relay PWB
Power Filter
PWB
(P1)x2
ø3x6mm
(P1)x4
ø3x6mm
(M1)x2
ø3x6mm
(N1)x3
ø3x6mm
(M1)x4
ø3x6mm
(M2)x5
h20mm
(M1)x4
ø3x6mm
(P2)x2
(Q1)x6
ø3x6mm
(Q3)x1
(Q2)x2
(M3)x2
Washer
Power
Support
PWB
1Bit Amp
PWB
Main Volume PWB
(U1)x4
ø3x16mm
(U1)x2
ø3x8mm
(M3)x1
(K2)x4
Soldering
(K3)x4
Main PWB
(U1)x2
ø3x8mm
(M3)x2
Washer
(S1)x6
ø3x12mm
(R2)x6
ø3x6mm (R2)x2
ø3x8mm
(S1)x4
ø3x10mm
(S1)x6
ø3x12mm
Power Switch
PWB
(R1)x2
Power PWB
Powet Heat
Cover
Figure 8-3
Figure 8-5
Figure 8-2
Figure 8-1
Figure 8-4
Shield
Cover B Shield
Cover C
Shield
Cover A
(H1)x6
ø3x8mm
(H1)x5
ø3x6mm
(H1)x1
ø3x6mm
(J1)x3
ø3x6mm
(J1)x4
ø3x8mm
(G1)x4
ø3x6mm
(G1)x3
ø3x6mm
(G1)x3
ø3x6mm
Bottom
Panel
(T1)x2
ø3x12mm
(T1)x7
ø3x6mm
Main Chassis Rear Panle
(T1)x4
ø3x12mm
(V1)x1
ø3x6mm
(V1)x4
ø3x6mm
(V1)x1
ø3x6mm
Front Panel
Main Chassis
Figure 8-6
(Z1)x5
ø2.6x5mm
(X1)x1 (X2)x1
(X3)x1
(X4)x1
(W1)x4
ø3x6mm
(W2)x1
(Y1)x12
ø3x6mm
(Z1)x8
ø2.6x5mm
System
Microcomputer
PWB
Switch1 PWB
Front
Panel
Front Panel
Bracket
LED PWB
Display Volume
PWB
Washer
Figure 8-7

SM-SX100
– 9 –
Figure 9-2
Figure 9-1
Note 1:
Positioning the volume joints
1. Rotate the sub volume shaft (inside of the set) so that the
flat side faces upward. Fasten the joints in numerical order
as shown in the in the figure.
2. Rotate anticlockwise both the main and sub shafts to mini-
mum level.
3. Slide the connecting shaft until it hits the joint coupling
sleeve.
4. Rotate the joint coupling and connecting shaft so that the
hexagonal screws face the direction of 12 and 9 o'clock.
Fasten the screw that face 12 o'clock.
5. Rotate the shaft and fasten the other hexagonal screws.
6.Rotatethevolumeshaftsothattheflatsidefacesdownward.
Fasten the hexagonal screw from below.
1 (Fasten)
2 (Fasten)
Display Volume
PWB Joint
Coupling
Fasten
Fasten
Fasten
Fasten
Keep the default setting,
"each interval = 1 mm."
Sleeve
Hub Hub
Fasten
Volume
Knob
Volume Connecting Shaft
Joint Coupling

SM-SX100
– 10 –
ADJUSTMENT
Measure the noise distribution between the set output terminals (Lch+, Lch- and Rch+, Rch-), and adjust VRA1 to VRA4.
The VRA adjustment sequence is the same as that of the offset voltage adjustment.
Measuring instrument: Yokokawa Electric brand SA2400
Measurement range : Refer to Fig. 10-2.
Adjustable range:
1
250Hz to 100kHz within ±3dB from the standard noise curve
2
(Noise strength of 125Hz) — (Noise strength of 250Hz) 20dB
AC POWER
SUPPLY
UNIT Specter
Analyzer
Speaker terminal
Apply the analyzer between Lch+ and Lch-,
and between Rch+ and Rch-.
Figure 10-1
Standard noise floor curve
(Frequency range 1)
Figure 10-2
20dBV ¨ ”

SM-SX100
– 11 –
1-bit PWB adjusting method
Connect as shown Fig. 11-1.
AC IN 110-120, 220-240, 230V
AC POWER SUPPLY
UNIT
Digital Multimeter
Oscilloscope
Figure 11-1
[Simplified offset voltage adjustment]
Connectthedigitalmultimetertotheterminalsofthespeaker,andadjustthevoltagebetween+and-ofeachterminalto0 ±10mV.
(Fig. 11-2)
(Adjusi from 4 ohms)
Voltage check SP
Terminal Impedance selector
SW Adjustment VOL
Rch 4 ohms VRA1
Rch 8 ohms VRA3
Lch 4 ohms VRA2
Lch 8 ohms VRA4
Figure 11-2
4 ohms and 8 ohms
SP terminal
Rch
Rch
Lch
Lch
Impedance
Selector SW (Parallel to SP terminal
on the upper side)
(Terminal Board Diagram)
* On both Lch and Rch, adjust the 4 ohms side earlier.
[Adjustment Check]
Connect the oscilloscope to the test point, and verify that the voltage span of the bottom figure confirmation. (Fig. 11-3)
5.0
}
1.0Vp-p
Check both L and R.
Lch T.P
Rch T.P
(VRA2)
(VRA4)
(VRA3)
(VRA1)
(1 BIT AMP. PWB)
Figure 11-3

SM-SX100
– 12 –
INTRODUCTION OF CIRCUIT OUTLINE
1. Technical background
1-1) Concept of coding technology
Though the PCM system is the most popular method to convert the analog audio signals into the digital codes, the basic
concept of the PCM system is that the signals are sampled with the frequencies whose band is two or more times of the
frequency band to be transferred and is quantized into the multi-bits.
In the other words, "sampling frequency Fs" and "quantized bit quantity" determine the frequency band (Fs/2) and the
dynamic range respectively for the information to be encoded.
As another concept against the PCM encoding which principally determine the transfer range, Shannon *1) establishes
the theory of the coding system which sets the transfer range with "average information quantity per unit time" from the
viewpoint of the information theory.
On method of this system is "high-speed sampling 1-bit coding" system which uses the modulation. The quantized
bit quantity has only 2 values of 1 bit but the sampling frequency is sufficiently increased to make it possible to gain the
transfer range which assures the dynamic range.
As two systems are compared with each other, it is said that the PCM system determines the dynamic range with the
quantizedbitquantity,"voltagedissolutionpower"butthe1-bitcodingsystem"increasestimeseparationpower"toassure
the purposed dynamic range.
On the PCM signal, when the quantized bit quantity is designated b, "signal to noise ratio (S/N)" of the quantized noise
to the signal is expressed as follows.
(S/N) dB = 6.02b + 1.76 dB
It shows that the ratio of signal to noise is improved in proportion to the increase of the quantized bit quantity.
When the quantized bit quantity is 16 and the signal is the sine wave, the ratio of signal to noise is practically gained as
follows.
(S/N) dB = 6.02 X 16 + 1.76 = 98.08 dB
On the other hand, Fig. 12-1 shows if "7th order feedback high-speed 1-bit quantizer" is used, the quantized noise
distribution can be controlled by timely setting the part feedback coefficient b1 to b3 in the algorithm.
Fig.12-2showsthatthequantizednoisemonotonouslyincreasestowardthehighrangeinthequantizednoisedistribution
incaseofb1tob3=0.Figs.12-3and12-4showthesamesamplingfrequencyasshowninFig.12-2butshowrespectively
the quantized noise distributions which gain "wide D range" and and "wide frequency range" respectively by changing the
values of b1 to b3.
As described above, even on the 1-bit signal of the same sampling frequency, "D range" and "frequency band" of the
transferred signal can be selected at the degree of freedom with the design of the the above algorithm coefficient.
Thoughthe1-bitsignalwhichisusedatSACDand1-bitamplifieristhe1-bitsignalof"64fs",itisdesignedwiththealgorithm
which can assure the wide transfer band (D range: 120 dB (<20 Hz), Frequency band: 100 kHz).
*1) C.E.Shannon, "A mathematical theory of communication, "Bel Syst. Tech.J.27, (1948).
Figure 12-1
Input
Multiplier
Adder
Delay unit
Quantizer
Output
Quantization
Figure 12-2
Figure 12-3 Figure 12-4
0dB
–50
–100
–150 100 1k 10k 20k 100kMz
0dB
–50
–100
–150 100 1k 10k 20k 100kMz
Wide D range
0dB
–50
–100
–150 100 1k 10k 20k 100kMz
Wide frequency band

SM-SX100
– 13 –
1-2) Application development of 1-bit coding technology
ThetechnologyhasbeenappliedinthefieldofAD/DAconversiondevice,anditiswellknownthat" modulation"isdone
in the intermediate process of the analog signal and multi-bit signal.
Since "1-bit signal" is nearer to "analog signal" than "multi-bit signal, it has been proven that it is effective for the record/
replay format of the audio signal. It is well known that it is introduced as <Super Audio CD> in the market.
It is particularly thought that the technology to generate the 1-bit signal, " modulation technology" is applied to the
amplifying operation. "1-bit amplifier" has been developed by directing the attention to this point.
2. Basic technological element " modulation technology"
2-1) Principle of modulation 1-bit signal generation
<modulation>
As the method to encode the analog signal into the 1-bit signals, " modulation coding system" is well known.
. In this system, the analog signal waveform is traced and encoded with the step waveform as follows.
. If the upward gradient of the input signal is large, it is coded as "1".
. If the downward gradient of the input signal is large, it is coded as "0".
This method is well known.
In the other words, the 1-bit signal gained through the modulation expresses the gradient of the analog signal, the size
of "differential value" with the frequencies of "0" and "1".
Figure 13-1 PRINCIPLE DIAGRAM OF MODULATION
Input
Output
Integrator Quantizer
1 sampled delay
Figure 13-2 EXPLANATORY DIAGRAM OF
MODULATION OPERATION
1Bit
Signal
Analog
Signal
Analog signal waveform
modulation
Example of 1-bit signal coding modulation
<modulation>
It is found that "code array corresponding to the amplitude" of the original signal will be produced if the input analog signal is
previously integrated. As this block diagram is shown in Fig. 13-3, this is the basic form of "primary modulation".
Figure 13-3 PRINCIPLE DIAGRAM OF PRIMARY MODULATION
Q
Z
0
01
1
0 1 0 1 0
–1
YX
Input
Integrator
1 sampled delay
Quantizer
Output
1Bit Signal
Analog Signal
+

SM-SX100
– 14 –
Figure 14-1 EXPLANATORY DIAGRAM OF MODULATION
101010001000010000000010101101111101110111111111111110101
ANALOG 0v-
1 BIT
SIGNAL
"0" Area
"1" Area
Integrator output : Lateral bar of thick line (-): 1
Lateral bar of doubled line (=): 0
Analog signal
waveform
Theoperationofthe modulationisexplainedusingFig.14-1.Here,theanalogsignalcomponentfromtheinputsection
isexpressed withtheblack-filledvector,and thebinaryvaluenegativelyfed backisexpressedwiththe white-blankvector.
In this block, the following operation is applied.
1
If the output of the integrator is "positive", subtraction of "positive unit vector" is applied to the input side.
(In the figure, the downward white-blank vector is added.)
2
If the output of the integrator is "native", subtraction of "negative unit vector" is applied to the input side.
(In the figure, the upward white-blank vector is added.)
If the output of the integrator increases or the amplitude of the input signal increases, the figure shows that the negative
feedback is applied to suppress the increase.
In the other words, the continuous "positive" output of the integrator means that the amplitude of the input signal is large,
and the frequency of "1" coding increases.
On the contrary, the continuous "negative" output of the integrator means that the amplitude of the input signal is small,
and the frequency of "0" coding increases.
Thus, "binary codes corresponding to the amplitude" can be gained through the operation of the modulation.
Figure 14-2 EXPLANATORY DIAGRAM OF MODULATION
Slant view of analog signal Front view of analog signal
1 Bit Signal 1 Bit Signal

SM-SX100
– 15 –
2-2) 7th order modulation circuit and devising
Ifany1-bitsignalisproducedthroughtheoperationofthe modulation,thequantizednoiseisexpelledtothehighrange.
This is well known as "noise shaping", and it is used to reduce the quantized noise of the target frequency band (example:
audibleband).Astheoperationof "primary modulation"isdescribed usingFig.15-1, itiswellknownthatthereduction
effect of the quantized noise is increased as the number of the order of the modulation is increased.
Quantized noise
Audible band
0fs/6 Frequency
7th order
5th order 3th order
0th order
Figure 15-1 NUMBER OF ORDER, AND NOISE SHAPING
The circuit here used to produce the 1-bit signal is practiced of "7th order modulation algorithm" as shown in Fig. 15-
2.
The strong noise shaping is applied to assure the wide dynamic range in the audible range.
Figure 15-2 7TH ORDER MODULATION ALGORITHM
Q
Q
Z
–1
Z
–1
Z
–1
Z
–1
Z
–1
Y
Output
Quantization
Adder Integrator Multiplier Delay unit Quantizer (–1 or +1)
Input
X
a
1
b
1
a
2
a
3
b
2
a
4
a
5
a
6
b
3
"7th order modulation LSI" gained by integrating the signal process circuit into one chip is shown in Fig. 15-3. As well
as the LSI can independently generate the 1-bit signals, the input terminal is provided to apply the feedback of the
modulation from the external in order to show the performance with the amplifying operation.
Figure 15-3 7TH ORDER MODULATION 1-CHIP LSI

SM-SX100
– 16 –
3. Application to amplifying circuit: 1-bit amplifier
3-1) Basic block and operational principle
The system classified as "Class C amplifier" among the amplification circuits switches the high voltage to control the ON
time in order to amplify the audio signal.
"PWM signal" which has the analog width in the time axis direction is generally used as the signal to control the switching.
The operational principle of Class D amplifier is developed to apply the said 7th order modulation 1-bit signal to the
signal which controls the signal. Thus, the 1-bit amplifier "SM-SX100" is introduced.
Figure 16 1-BIT AMP. SM-SX100 BLOCK DIAGRAM
Volume
Control
Analog Signal
1-Bit Signal
Function Indicator
Function Switch
Analog Signal
Input
Line 1 (RCA PIN)
Line 2 (Canon)
SACD (Analog)
SACD (1bit)
Digital 1(ST LINK)
Digital 2(RNC)
Digital 3(RCA)
Digital 4(TOS LINK)
1-Bit Signal Input
Multi-Bit Signal
Input Terminal
Digital
Interface
Circuit
Sampling Rate
Converter
Circuit
Circuit of 1-Bit
Conversion
From Multi-Bits
Volume Indicator
LED Driver Circuit
LED Driver Circuit
Control
Microcomputer
1-Bit Amplification Signal Process Circuit
Power Switching
Circuit
Digital Driver
Circuit
7th Order
∆∑ Modulation
1-Bit Signal
Generation Circuit
∆∑ Dynamic Feedback
–22V
DC Power
Supply Circuit
DC Power
Supply Circuit
Low-Pas Filter
Circuit
Bi-wiring Speaker
Terminal
Speaker
Fuse Power
Switch
Switching
Power Circuit
+32V
–32V
+5V +5V
+5V
+12V –12V
Digital 1 Digital 2 Digital 3 Digital 4 SACDAnalog 1 Analog 2
Digital 1 Digital 2 Digital 3 Digital 4 SACD Analog 1 Analog 2
Fig. 16 shows the basic block of the 1-bit amplifier. In the block diagram, the core of the amplifying operation is "1-bit
amplification signal process circuit", being composed of the following four circuits.
1
7th order modulation 1-bit signal generation circuit
2
Digital driver circuit
3
Power switching circuit
4
Low pass filter circuit
In the circuit
1
, the input signal is processed through the high-speed sampling modulation circuit to generate "1-bit
signal array" which is directly coded from the input information. (Said 7th order modulation LSI)
Thoughthe1-bitsignalisused as the control signal to switch theconstant-voltagepowersupplyatthetimingof the quartz
precision, the digital driver circuit
2
controls the drive, suppressing the delay to the minimum since the full bridge power
switching circuit
3
composed of Power MOS-FET is operated at the high speed.
Thoughtheconstantvoltageissuppliedtothepowerswitchingcircuit
3
,thefluctuationnoiseincludedinthepowersupply
and the error component of the power switching are included in the output section of
3
. Therefore, the " dynamic
feedback" loop which negatively feeds the information of the output section back to "7th order modulation 1-bit signal
generation circuit
1
" at the high speed is provided to compensate the above fluctuation noise and error component at the
real time. The feedback operation achieves "power amplification faithful to input signal" without influence of the power
fluctuation and so on.
Sincethe 1-bitsignalof64fsoriginallycatchesthe analogsignalatthesamplingfrequencyof 64x44.1kHz=2.8224MHz,
the information can be transferred to the band of approx. 1.4 MHz, a half of the sampling frequency as the principle.
In the practical circuit, the band is limited at 100 kHz as the result of the following being considered to determine the pass
band.
1)Thequantized noise of the 1-bit signal increases toward the high range, and iteliminatesthebandwherethequantized
noise increases in the high range.
2) If any high frequency component of 100 kHz or more is included in the analog signal when an analog signal is taken out
of the 1-bit signal, an abnormality will occur in the circuit system and transfer system of the following step. (Example:
High frequency oscillation, unnecessary radiation, tweeter breakage, etc.)
3) The frequency component of the acoustic signal which is present in the natural is distributed in the band up to 100 kHz.
In the low pass filter circuit
4
of the last step, the components up to 100 kHz are taken out from the the switching signal
for which the voltage is converted, and are output as the analog signal for the speaker drive.

SM-SX100
– 17 –
3-2) The feature of 1-bit amplifier
As described above, the amplification principle whose viewpoint is different from that of the existing analog amplifying
circuit assures S/N in the audible band, thus achieving the audio amplification which has the wider band.
Moreover, the operation which converts the voltage through the switching operation approximately halves the power
consumption during the ordinary operation in comparison with the existing analog amplifier, thus reducing the heating
amountofthe amplifyingsectiontoapprox. 1/5.Inadditionto the highlyfaithfulreplayof theaudiosource,it achievesboth
energy saving and compactness/high power at the same time.
On the other hand, an countermeasure to suppress the noise in the power amplification with the switching operation
becomesinevitable.Particularlyagainstthepowerlinenoiseandunnecessaryradiation,thecountermeasureistakenfrom
both sides of the circuit (minimization of coring and circuit loop) and the structure (double shield of steep plate and copper
plate), thus clearing the technical standard of the electricity operation.
Moreover, the input terminal unit is provided with the originally specified 1-bit signal input terminal in addition to the three
analog systems and four digital audio interface systems. This terminal is provided to be connected to SACE player of our
company which will be put on sale in near future, being specified to transmit the 1-bit signal after the player is mutually
recognized as the countermeasure against the illegal copy.
Theanalogsignalsofthethreesystemsareselectedwiththerelaycircuitbythefunction, and the attenuation level is then
setwith thevolume.Thissignalisconnectedtothe analoginputpinofthe7thorder modulation1-bit signalgeneration
circuit, and the aforementioned "signal process of 1-bit amplifier" is applied.
The digital signals (multi-bit signals) of the four systems are input in the format of the audio interface but the sampling
frequency corresponds to 32 kHz/44.1 kHz/48 kHz. These plural sampling frequencies are converted to 44.1kHz by
"sampling rate converter circuit". This signal is farther oversampled, and "64fs 1 bit signal" is generated by "multi-bit to 1
bit conversion circuit".
Since the 1-bit signal which is output includes the analog information coded in the original digital signal, the analog sound
volume level can be adjusted by controlling the wave height value of the 1-bit signal itself with the volume.
The signal is differentially connected to the digital input pin of the 7th order modulation 1-bit signal generation circuit,
and the aforementioned "signal process of 1-bit amplifier" is applied like the analog signal.
From the special terminal of SACD, the 64fs clock of the SACD player side is supplied.
Asaforementioned,theanalogsoundvolumelevelcanbeadjustedbycontrollingthewaveheightvalueofthesignalitself.
The signal is differentially connected to the digital input pin of the 7th order modulation 1-bit signal generation circuit,
and the aforementioned "signal process of 1-bit amplifier" is applied like the analog signal.

SM-SX100
– 18 –
EXPLANATION OF 1-BIT UNIT
1. modulation 1-bit conversion circuit
The analog signals input from CNPA1 and CNPA2 are input from the terminals 17 and 20 of ICA1. At the input step of ICA1,
the signal input signal is regarded as the differential input signal, and the switching signal which is later called "dynamic
feedback" is attenuated and is regarded as the level-shifted negative feedback signal.
They are added, and is transmitted to the differential type primary integrator of the modulation 1-bit conversion circuit.
After they are integrated by the 2nd to 7th order integrator group, the integrated values of 2nd to 7th are added with the adder.
Theadded result is compared with Vdd/2 (=2.5 V) by thecomparator,andis quantized. As the result, the 1-bit signal is gained.
Since the modulation circuit operates at 128fs (= 5.6448 MHz, fs = 44.1 kHz), the 1-bit signal exceeds the limit of the
switching speed of the power MOS-FET which is the switching element of the switching circuit of the later step.
Therefore,thesignal is passedthroughthedouble widthconversioncircuitwhich doubles thepulsewidthto 64fs, andisoutput
from the terminals 2, 3, 5 and 6.
After the limiter is applied to the digital signal input from CNPA3 and CNPA4 at ZDA81 to ZDA84, it is directly transmitted to
the differential type primary integrator of the modulation circuit from the feedback terminals 14, 15, 22 and 23. The signal
process hereafter is the same as that of the analog signal.
2. Switching logic circuit
The output signal of ICA1 is distributed to FET driver IC for the full bridge in the switching circuit by ICA2 and ICA3 of the logic
circuit IC.
3. Level shift circuit
Though the output is L (0 V) or H (5 V) in ICA2 and ICA3, they shift the level from the reference voltage -32 V of the FET driver
IC to L (-32 V) and H (-22 V) with QA1 to QA8 and 1 kohms (RA45 to RA52) and 390 ohms (RA37 to RA44), and it is used as
the FET drive signal.
4. FET driver circuit
In the bridge circuit composed using the N channel power MOS-FET, the source of the power MOS-FET of the high side
fluctuates in the potential in the output state, being the floating drive type.
Accordingly,theauxiliarypowersupplyto supply the power to the gate becomesnecessary.Here,thebootstrapcircuitis used
as the auxiliary power supply.
When H (-22 V) is supplied to the terminal No. 6 of FET driver IC (ICA4 to ICA7), the terminal No. 8 is driven to turn on FET
of the low side. As shown in the illustration of the boot strap circuit, the current
1
flows, and the electric charge is accumulated
in the boot strap capacitor C. In the practical circuit, it corresponds to CA36 to CA39 connected to the terminal 2.
When H (-22 V) is applied to the terminal 5, the terminal 3 is driven to turn on FET of the high side.
At this time, the electric charge accumulated at
1
is discharged, and the current
2
flows to charge Cgs of FET as shown in
the illustration of the boot strap circuit.
5. Power switching circuit
+32 V and -32 V are switched with the power MOS-FET (QA9 to QA16).
(When the impedance switch is a 4 ohms load, +24 V and -24 V are applied.)
6. Low pass filter circuit
From the signal switched by the power switch circuit, the analog signal is picked out by the low pass filter composed of the 4th
order Butterworth type of the cutoff frequency 100 kHz.
7. Dynamic feedback circuit (feedback circuit)
The signal which is switched with the power switching circuit is divided by the resistors of the fixed type of 6.8 kohms (RA101,
RA102),semi-fixedtype of 200 ohms (VRA1, VRA2) and the fixed type of 680 ohms(RA61andRA62)onthevariable side and
the fixed type of 6.8 kohms (RA103 and RA104) and the fixed type of 750 ohms (RA63 and RA64), and is attenuated to +5 V,
0 V.
RLYA1 turns on the relay when the impedance switch is a 8 ohms load to change the resistance division ratio.
The attenuated +5 V, 0 V signal is shifted to the level of Vdd/2 of the terminals 18 and 19 through the resistor (RA91 to RA94),
and is input to the feedback terminals 14, 15, 22 and 23 as the signal of +2.5 V and -2.5 V.

SM-SX100
– 19 –
14/23
17/20IN
15/22
NF(+)
NF(–)
-1 -1
Integrator/Adder
Group Comparator Double width
conversion
Input Step
Figure 19-1 MODULATION 1-BIT CONVERSION CIRCUIT
Vs
1
2
4
Q1
Q2
C
Rii
CGS
X
point
Y point
Diode prevents
i
2
from
returning to Vs.
Q2 is turned on,
and the holding
gate voltage is
gained from C.
It is necessary to
periodically
charge C.
Figure 19-2 BOOT STRAP CIRCUIT
• Protect circuit
When the protect circuit is activated, the speaker relays RLY107 and RLY108 and the power relay RLY106 are turned off, and
the function switch key is not received.
When the power switch is turned off, it is once reset.
For detection, the overcurrent detection circuit and the output offset detection circuit are provided and the relays and so on are
controlled by the microcomputer.
• Current detection section (Fig. 20-1)
IfanyovercurrentflowsinR256,thepotentialdifferencewillbegeneratedbothendsofR256tosupplyittoPins2and3ofIC201.
Iftheoutputsignal from Pin 1oftheoutputof IC201 is suppliedtothecomparatorIC201 (Pins 5 to7)(throughthetime constant
circuit) and reaches the level of the specified value or more, the comparator will be activated to set H at Pin 7. Then, the
transistors Q201 and Q202 will be turned on, and the signal of H level will be supplied to Pin 27 of the microcomputer IC904.
Thus, the protect will be activated.
• Offset detection section (Fig. 20-2)
If any potential difference is generated between the terminals of the speaker (L+ and L- as an example), the potential which
drives Q651 and Q653 will stand at the terminal connected section of the emitter of Q651 or the base of Q653, and either will
be turned on. (Pin 1 of IC651 as reference)
(If + level is established, Q653 will be turned on, and if - level is established, Q651 will be turned on.)
IfQ651,Q653orQ652,Q654areturnedon,Q201willbeactivatedlikethesaidcurrentdetectiontosupplythesignalofHlevel
to Pin 27 of the microcomputer IC904.

SM-SX100
– 20 –
Figure 20-1 OVERCURRENT DETECTION CIRCUIT
4
1
3
2
5
67
8
From OFF-SET Detection Section
R256
Detection
Resistor
R228
10K
(VRN)
R227
100K
(VRN)
C614
0.01
R202
47K
(VRN)
C201
0.01
Q202
2SC2412 KR
Q210
2SC2412 KR
Q208
2SC2412 KR
D202
DA119
R203
100K
(VRN)
R204
10K
(VRN)
R233
100K
R206
100K
(VRN) D203
DA119
R205
10K
(VRN)
Q201
2SA1037 KR
R201
100K
(VRN)
D204
DA119
D206
DA119
R214
10K
(VRN) R213
10K
(VRN)
R211
4.7K
(VRN) R210
47K
(VRN)
R209
4.7K
(VRN)
R208
4.7K
(VRN)
C205
0.01
C204
0.01
C203
0.01
C219
10/25
R212
4.7K
(VRN)
C218
10/25
R180
2.7K
(VRN)
R179
100K
(VRN)
Q116
2SC2412KR
D107
DA119
RLY106
R207
47K
(VRN)
C202
0.01C313
0.01
R217
100K
(VRN)
C207
0.01
To µ-com
CNP106 Pin 12
IC904
Pin 27
+
–
+
–
MAIN PWB-A1(3/3)
1
4
3
2
75
6
8
C655
0.01
C654
0.01
R659
47K
R658
22K
R657
22K
R661
10K
C653
47/50
IC651
NJM4558M
MOTOR DRIVER
+32V +B
MAIN-A
+15V
–15V
–32V
+32V
R660
4.7K R652
15K
R654
15K R656
10K
C652
33/50
D652
DA119
D651
DA119
R653
15K
R651
15K
C651
33/50
R655
10K
Q652
2SC2412KR
Q653
2SC2412KR
Q651
2SC2412KR
Q654
2SC2412KR
–15V
–B
–B –B
–B –B
+B
–32V
+15V +B
+B
+B
P29 9 - H,12 - C,12 - G
TO MAIN SECTION
L+
L–
R+
R–
A
3
4
6
5
B
C
E
D
Figure 20-2
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