OKI MSM7603

E2U0064-18-82
¡ Semiconductor
MSM7603/7603B
¡ Semiconductor
This version:
Aug. 1998
MSM7603/7603B
Echo Canceler
GENERAL DESCRIPTION
The MSM7603/7603B is an improved version of the MSM7602 with basically the same
configuration, and offers twice the cancelable echo delay time of the MSM7602.
The MSM7603B I/O interface allows switching between m-law PCM and A-law PCM.
The MSM7603/7603B is a low-power CMOS IC device for canceling echo (in an acoustic system
or telephone line) generated in a speech path.
Echo is canceled, in digital signal processing, by estimating the echo path and generating a
pseudo echo signal.
When used as an acoustic echo canceler, the device can cancel the acoustic echo, between the loud
speaker and the microphone, which occur during hands free communication such as on a cellular
phone or a conference system phone.
When used as a line echo canceler, the device can cancel the line echo which returns due to
impedance mismatching in a hybrid.
In addition, a quality conversation is made possible by controlling the level and by preventing
howling through a howling detector, double talk detector, attenuation function and a gain
control function, and by controlling the low level noise by means of a center clipping function.
The use of a single chip codec, such as the MSM7704 (3 V) and MSM7533 (5 V), allows an economic
and efficient echo canceler to be configured.
FEATURES
• Can handle both acoustic and telephone line echoes.
• Switchable between m-law PCM and A-law PCM interfaces. (MSM7603B)
• Cancelable echo delay time:
MSM7603B-003 .............. 55 ms (max.)
• Echo attenuation
: 30 dB (typ.)
• Clock frequency
: 19.2 MHz
17.5 MHz to 20 MHz (when internal sync signal not used)
• Power supply voltage : 2.7 V to 5.5 V
• Package:
28-pin plastic SSOP (SSOP28-P-485-0.65-K) (Product name : MSM7603-003GS-K)
(Product name : MSM7603B-003GS-K)
1/20
¡ Semiconductor
MSM7603/7603B
BLOCK DIAGRAM
MSM7603/7603B
RIN
S/P
Non–linear/
Linear
ATT
Howling
Detector
Double Talk
Detector
Power
Calculator
Linear/
Non–linear
Gain
P/S
ROUT
Adaptive
FIR Filter
(AFF)
–
SOUT
P/S
Linear/
Non–linear
Center
Clip
ATT
+
+ Non–linear/
Linear
S/P
SIN
RST
PWDWN
Clock Generator
VDD
Mode Selector
I/O Controller
PLL
CLKIN
*
VSS
SCKO SYNCO
NLP HCL ADP ATT GC
HD m/A
SCK SYNC
For MSM7603B only
2/20
¡ Semiconductor
MSM7603/7603B
PIN CONFIGURATION (TOP VIEW)
NLP 1
28 VDD
HCL 2
27 SOUT
ADP 3
26 ROUT
SYNC 4
25 SIN
SCK 5
24 RIN
VDD 6
23 VSS
VSS 7
22 NC
RST 8
21 NC[TEST]*
PWDWN 9
20 VDD
HD 10
19 ATT
VDD[m/A]* 11
18 SCKO
17 GC
CLKIN 12
VDD(PLL) 13
16 SYNCO
VSS(PLL) 14
15 VSS
NC : No connect pin
28-Pin Plastic SSOP
*
Pins shown in brackets apply to MSM7603B.
3/20
¡ Semiconductor
MSM7603/7603B
PIN DESCRIPTIONS
Pin
Symbol
Type
1
NLP
I
Description
This is the control pin for the center clipping function to force
the SOUT output to a minimum value when the SOUT signal is
below –57 dBm0. Effective for reducing low-level noise.
"H": Center clip ON
"L": Center clip OFF
2
HCL
I
This is the through mode control pin.
When this pin is in the through mode the RIN and SIN data are
output to ROUT and SOUT. At the same time, the coefficient of
the adaptive FIR filter is cleared.
"H": Through mode
"L": Normal mode (echo canceler operates)
3
ADP
I
This is the AFF coefficient control pin which stops updating the
adaptive FIR filter (AFF) coefficient and sets it to a fixed value,
when the pin is configured to be the coefficient fix mode.
Used when holding the AFF coefficient which has been once
converged.
"H": Coefficient fix mode
"L": Normal mode (coefficient update)
4
SYNC
I
This is the input pin for the sync signal for transmit/receive
serial data. This pin uses the external SYNC or SYNCO.
Inputs the PCM codec transmit/receive sync signal (8 kHz).
5
SCK
I
This is the clock input pin for transmit/receive serial data. It
uses the external SCK or the SCKO.
Input the PCM codec transmit/receive clock (64 to 2048 kHz).
4/20
¡ Semiconductor
MSM7603/7603B
PIN DESCRIPTIONS (Continued)
Pin
Symbol
Type
8
RST
I
Description
This is the input pin for the reset signal.
"L": Reset mode
"H": Normal operation mode
Due to initialization, input signals are disabled for 100 ms after reset
(after RST is returned from "L" to "H").
Input the basic clock during the reset.
Output pins during the reset are in the following sates :
High impedance: SOUT, ROUT
Not affected: SYNCO, SCKO
9
PWDWN
I
This is the power-down mode control pin for power down operation
"L": Power-down mode
"H": Normal operation mode
During power-down mode, all input pins are disabled and output
pins are in the following states :
High impedance : SOUT, ROUT
"L": SYNCO, SCKO
Reset after the power-down mode is released.
10
HD
I
This pin controls the howling detect function that detects and
cancels a howling generated during hands-free talking for
acoustic system.
This function is used to cancel acoustic echoes.
"L": Howling detector ON
"H": Howling detector OFF
11
(m/A)
I
Used for MSM7603B only.
This is the input pin for m-law PCM/A-law PCM interface select
signal.
"L": A-law PCM interface
"H": m-law PCM interface
For MSM7603, apply VDD.
12
CLKIN
I
This is the input pin for external input for the basic clock.
Input the basic clock (17.5 to 20 MHz).
When the internal sync signal (SYNCO, SCKO) is used, input the
basic clock of 19.2 MHz.
13
VDD (PLL)
I
This is the power supply pin for the PLL circuit used for the basic
clock.
Insert a 0.1 mF capacitor with excellent high frequency
characteristics between VDD (PLL) and VSS (PLL).
14
VSS (PLL)
I
This is the ground pin for the PLL circuit used for the basic clock.
16
SYNCO
O
This is the output pin for the 8 kHz sync signal for the PCM codec.
Connect to the SYNC pin and the PCM codec transmit/receive sync
pin.
Leave open if using an external SYNC.
5/20
¡ Semiconductor
MSM7603/7603B
PIN DESCRIPTIONS (Continued)
Pin
Symbol
Type
17
GC
I
Description
This is the pin for the input signal by which the gain controller
for the RIN input is controlled. The pin also controls RIN input
level and prevents howling.
The gain controller adjusts the RIN input level when it is –20
dBm0 or above. RIN input levels from –20 to –11.5 dBm0 will be
suppressed to –20 dBm0 in the attenuation range from 0 to 8.5 dB.
RIN input levels above –11.5 dBm0 will always be attenuated by
8.5 dB.
"H": Gain control ON
"L": Gain control OFF
"H" is recommended for performing echo cancellation.
18
SCKO
O
This is the output pin for the transmit clock signal (256 kHz) for
the PCM codec.
Connect to the SCK pin and the PCM codec transmit/receive clock
pin.
Leave open when using an external SCK.
19
ATT
I
This is the control pin for the ATT function which prevents howling
by attenuators (ATT) for the RIN input and SOUT output.
If there is input only to RIN, then the ATT for the SOUT output is
activated.
If there is no input to SIN or there is input to both SIN and RIN,
then the ATT for the RIN input is activated.
Either the ATT for the RIN output or the ATT for the SOUT is
always activated in all cases, and the attenuation of ATT is 6 dB.
"H": ATT OFF
"L": ATT ON
"L" is recommended for performing echo cancellation.
21
(TEST)
O
This pin is for MSM7603B only and not used. Should be left open.
In MSM7603 it is an NC pin.
24
RIN
I
This is the receive serial data input pin.
Input the PCM signal synchronized to SYNC and SCK.
Data is read at the falling edge of SCK.
25
SIN
I
This is the transmit serial data input pin.
Input the PCM signal synchronized to SYNC and SCK.
Data is read at the falling edge of SCK.
26
ROUT
O
This is the output pin for receive serial data.
Outputs the PCM signal synchronized to SYNC and SCK.
This pin is in high impedance state during the absence of data output.
27
SOUT
O
This is the output pin for transmit serial data.
Outputs the PCM signal synchronized to SYNC and SCK.
This pin is in high impedance state during the absence of data output.
6/20
¡ Semiconductor
MSM7603/7603B
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Power Supply Voltage
VDD
Input Voltage
VIN
Power Dissipation
Storage Temperature
Condition
Rating
Unit
–0.3 to + 7
V
Ta = 25˚C
–0.3 to VDD + 0.3
V
1
W
—
–55 to +150
˚C
PD
TSTG
RECOMMENDED OPERATING CONDITIONS
(VDD = 2.7 V to 3.6 V)
Symbol
Condition
Min.
Typ.
Max.
Unit
Power Supply Voltage
VDD
—
2.7
3.3
3.6
V
Power Supply Voltage
VSS
—
—
0
—
V
High Level Input Voltage
VIH
—
2.0
—
VDD
V
Low Level Input Voltage
VIL
—
0
—
0.5
V
Operating Temperature
Ta
—
–40
+25
+85
˚C
Symbol
Condition
Min.
Typ.
Max.
Unit
Power Supply Voltage
VDD
—
4.5
5
5.5
V
Power Supply Voltage
VSS
—
—
0
—
V
High Level Input Voltage
VIH
—
2.4
—
VDD
V
Low Level Input Voltage
VIL
—
0
—
0.8
V
Operating Temperature
Ta
—
–40
+25
+85
˚C
Parameter
(VDD = 4.5 V to 5.5 V)
Parameter
7/20
¡ Semiconductor
MSM7603/7603B
ELECTRICAL CHARACTERISTICS
DC Characteristics
Parameter
(VDD = 2.7 V to 3.6 V, Ta = –40˚C to +85˚C)
Symbol
Condition
High Level Output Voltage
VOH
IOH = 40 mA
Low Level Output Voltage
Min.
Typ.
Max.
Unit
2.2
—
VDD
V
VOL
IOL = 1.6 mA
0
—
0.4
V
High Level Input Current
IIH
VIH = VDD
—
0.1
1
mA
Low Level Input Current
IIL
VIL = VSS
–1
–0.1
—
mA
High Level Output Leakage Current
IOZH
VOH = VDD
—
0.1
1
mA
Low Level Output Leakage Current
IOZL
VOL = VSS
–1
–0.1
—
mA
—
30
50
mA
—
0.5
1
mA
Power Supply Current
(Operating)
Power Supply Current
(Standby)
Input Capacitance
Output Load Capacitance
IDDO
IDDS
—
PWDWN = "L"
CI
—
—
—
15
pF
CLOAD
—
—
—
20
pF
(VDD = 4.5 V to 5.5 V, Ta = –40˚C to +85˚C)
Parameter
Symbol
Condition
IOH = 40 mA
High Level Output Voltage
VOH
Low Level Output Voltage
VOL
IOL = 1.6 mA
High Level Input Current
IIH
VIH = VDD
Min.
Typ.
Max.
Unit
4.2
—
VDD
V
0
—
0.4
V
—
0.1
10
mA
IIL
VIL = VSS
–10
–0.1
—
mA
High Level Output Leakage Current
IOZH
VOH = VDD
—
0.1
10
mA
Low Level Output Leakage Current
IOZL
VOL = VSS
–10
–0.1
—
mA
—
40
70
mA
—
0.5
1
mA
Low Level Input Current
Power Supply Current
(Operating)
Power Supply Current
(Standby)
Input Capacitance
Output Load Capacitance
IDDO
IDDS
—
PWDWN = "L"
CI
—
—
—
15
pF
CLOAD
—
—
—
20
pF
8/20
¡ Semiconductor
MSM7603/7603B
Echo Canceler Characteristics (Refer to Characteristics Diagram)
Parameter
Symbol
Condition
Min.
Typ.
Max.
Unit
—
30
—
dB
—
—
55
ms
RIN = –10 dBm0
(5 kHz band white noise)
Echo Attenuation
LRES
E. R. L. (echo return loss)
= 6 dB
TD = 50 ms
ATT, GC, NLP: OFF
RIN = –10 dBm0
Cancelable Echo Delay Time
TD
(5 kHz band white noise)
E. R. L. = 6 dB
ATT, GC, NLP: OFF
9/20
¡ Semiconductor
MSM7603/7603B
AC Characteristics
Parameter
Clock Frequency
When Internal Sync Signal is not used
Clock Cycle Time
When Internal Sync Signal is not used
Clock Duty Ratio
Clock "H" Level Pulse Width
fc = 19.2 MHz
Clock "L" Level Pulse Width
fc = 19.2 MHz
Clock Rise Time
Clock Fall Time
(Ta = –40˚C to +85˚C)
Symbol
fC
VDD = 2.7 V to 3.6 V
Min.
Typ.
Max.
VDD = 4.5 V to 5.5 V
Min.
Typ.
Max.
—
19.2
—
—
19.2
—
17.5
—
20.0
17.5
—
20.0
Unit
MHz
—
52.08
—
—
52.08
—
50.0
—
57.14
50.0
—
57.14
tDMC
40
—
60
40
—
60
ns
tMCH
20.8
—
31.3
20.8
—
31.3
ns
tMCL
20.8
—
31.3
20.8
—
31.3
ns
tr
—
—
5
—
—
5
ns
tMCK
ns
tf
—
—
5
—
—
5
ns
tDCM
—
—
40
—
—
40
ns
fCO
—
256
—
—
256
—
kHz
Internal Sync Clock Output Cycle Time
tCO
—
3.9
—
—
3.9
—
ms
Internal Sync Clock Duty Ratio
tDCO
—
50
—
—
50
—
%
Internal Sync Signal Output Delay Time
tDCC
—
—
5
—
—
5
ns
Internal Sync Signal Period
tCYO
—
125
—
—
125
—
ms
Internal Sync Signal Output Width
tWSO
—
tCO
—
—
tCO
—
ms
Transmit/Receive Sync Clock Frequency
fSCK
64
—
2048
64
—
2048
kHz
Transmit/Receive Sync Clock Cycle Time
tSCK
0.488
—
15.6
0.488
—
15.6
ms
Transmit/Receive Sync Clock Duty Ratio
tDSC
40
50
60
40
50
60
%
Transmit/Receive Sync Signal Period
tCYC
123
125
—
123
125
—
ms
tXS
45
—
—
45
—
—
ns
tSX
45
—
tCYC-tSCK
45
—
tCYC-tSCK
ns
Sync Clock Output Time
Internal Sync Clock Frequency
Sync Timing
tWSY
tSCK
—
—
tSCK
—
—
ms
Receive Signal Setup Time
tDS
45
—
—
45
—
—
ns
Receive Signal Hold Time
tDH
45
—
—
45
—
—
ns
Receive Data Input Time
tID
—
7tSCK
—
—
7tSCK
—
ms
tSD
—
—
90
—
—
90
ns
tXD
—
—
90
—
—
90
ns
Sync Signal Width
Serial Output Delay Time
Reset Signal Input Width
tWR
1
—
—
1
—
—
ms
Reset Start Time
tDRS
5
—
—
5
—
—
ns
Reset End Time
tDRE
—
—
52
—
—
52
ns
Processing Operation Start Time
tDIT
100
—
—
100
—
—
ms
Power Down Start Time
tDPS
—
—
111
—
—
111
ns
Power Down End Time
tDPE
—
—
15
—
—
15
ns
Reset Pulse Width Immediately after Power Down tWPR
10
—
—
10
—
—
ns
Control Pin Setup Time (RST)
tDSR
20
—
—
20
—
—
ns
Control Pin Hold Time (RST)
tDHR
20
—
—
20
—
—
ns
Control Pin Setup Time
tDTS
0
—
—
0
—
—
ns
Control Pin Hold Time
tDTH
160
—
—
160
—
—
ns
10/20
¡ Semiconductor
MSM7603/7603B
TIMING DIAGRAM
Clock Timing
fC, tMCK, tDMC
tMCH
tr
tMCL
tf
CLKIN
tDCM
tDCM
SCKO
tDCO
fCO, tCO
SCKO
tDCC
tDCC
tCYO
SYNCO
tWSO
Serial Input Timing
fSCK, tSCK
tDSC
SCK
tSX
tXS
tCYC
SYNC
tWSY
tDH
tDS
SIN
RIN
MSB
7
6
5
4
3
2
1
LSB
0
MSB
7
tID
11/20
¡ Semiconductor
MSM7603/7603B
Serial Output Timing
fSCK, tSCK
tDSC
SCK
tSX
tXS
SYNC
tCYC
,
tWSY
tXD
tSD
tXD
SOUT
ROUT
High-Z
MSB
7
6
5
4
3
2
1
LSB High-Z
0
MSB
7
Operation Timing After Reset
tWR
RST
*Reset timing can be asynchronous.
tDIT
tDRS
tDRE
Internal operaion
Reset
Initialization
Processing Start
* INT is invalid during the shaded interval.
Power Down Timing
PWDWN
tDPS
Internal Operation
tDPE
Power Down
Processing Start
tWPR
RST
Invalid
12/20
¡ Semiconductor
MSM7603/7603B
Control Pin Load-in Timing
tWR
RST
tDHR
tDSR
NLP, HCL, HD,
ATT, ADP, GC
SCK
tCYC
SYNC
SIN
RIN
MSB
7
6
5
4
3
2
1
LSB
0
MSB
7
tID
tDTS
tDTH
NLP, HCL, HD,
ATT, ADP, GC
13/20
¡ Semiconductor
MSM7603/7603B
HOW TO USE THE MSM7603/7603B
The MSM7603/7603B cancels, based on the RIN signal, the echo which returns to SIN.
Connect the base signal to the R side and the echo-generated signal to the S side.
Connection Methods According to Echoes
Example 1:
Canceling acoustic echo (to handle acoustic echo from line input)
MSM7603
MSM7603B
ROUT
Acoustic echo
RIN
AFF
CODEC
Example 2:
–
+
SIN
H
CODEC
Line input
SOUT
+
Canceling line echo (to handle line echo from microphone input)
MSM7603
MSM7603B
Microphone input
RIN
ROUT
AFF
CODEC
–
SOUT
+
+
H
CODEC
SIN
Lin echo
Example 3: Canceling of both acoustic and line echo
(to handle both acoustic echo from line input and line echo from microphone input)
Microphone input
SOUT
–
Acoustic echo CODEC
RIN
AFF
SIN
+
–
+
+
ROUT
MSM7603
MSM7603B
SOUT
For acoustic echo
RIN
Line input
SIN
+
MSM7603
MSM7603B
AFF
ROUT
CODEC
H
Line echo
For line echo
14/20
¡ Semiconductor
MSM7603/7603B
ECHO CANCELER CHARACTERISTICS DIAGRAM
(for m-law and A-law, and for reference only)
RIN input level vs. echo attenuation
40
40
30
30
Echo attenuation [dB]
Echo attenuation [dB]
E. R. L. vs. echo attenuation
20
10
0
20
10
0
40
30
20
10
0
–50 –40 –30 –20 –10
–10
E. R. L. [dB]
0
RIN input level [dBm0]
Measurement Conditions :
RIN input = –10 dBm0 5 kHz band white noise
Echo delay time TD = 50 ms
ATT, GC, NLP = OFF
Power supply voltage 5 V
Measurement Conditions :
RIN input: 5 kHz band white noise
Echo delay time TD = 50 ms
E.R.L. = 6 dB
ATT, GC, NLP = OFF
Power supply voltage 5 V
Echo delay time vs. echo attenuation
Echo attenuation [dB]
30
Measurement Conditions :
RIN input = –10 dBm
5 kHz band white noise
20
10
E.R.L. = 6 dB
ATT, GC, NLP = OFF
Power supply voltage 5 V
0
0
10
20
30
40
50
Echo delay time [ms]
Note:
Above characteristics are for the MSM7533 (VDD 5 V, m-law CODEC interface). For the
MSM7704 (VDD 3 V, m-law interface) the characteristics are basically the same except
for input and output levels. Refer to the PCM CODEC data sheet.
MSM7533 (for both transmit and receive)
0 dBm0 = 0.85 Vrms = 0.8 dBm (600 W)
MSM7704 (for transmit side)
0 dBm0 = 0.35 Vrms = –6.9 dBm (600 W)
(for receive side)
0 dBm0 = 0.5 Vrms = –3.8 dBm (600 W)
15/20
¡ Semiconductor
MSM7603/7603B
Measurement System Block Diagram
White noise generator
TD
L. P. F. RIN
5 kHz
RIN
ROUT
MSM7603
MSM7603B
Level meter
SOUT
SIN
SOUT
Power supply voltage 5 V
Delay
Echo delay time
ATT
E. R. L.
(Echo Return Loss)
2ch CODEC
MSM7533
16/20
¡ Semiconductor
MSM7603/7603B
APPLICATION CIRCUIT
Bidirectional Connection Example
Microphone input
C1
2ch CODEC
MSM7533VGS-K
R1
R2
R3
DV
Speaker output
13
12
14
10
16
19
5
6
DV
DV
For cancelation of
acoustic echo
MSM7603/7603B
R4
25
SIN
26
ROUT
16
SYNCO
18
SCKO
9
PWDWN
8
RST
12
CLKIN
PWDWN
RST
CLK
DV
6
VDD
20 V
DD
28 V
DD
+
R1=20 kW
R2=20 kW
R3=2.2 kW
R4=10 kW
R9=10 kW
NLP
HCL
ADP
ATT
GC
HD
(m / A)
(TEST)
VDD(P)
VSS(P)
VSS
VSS
VSS
Line output
DV
AV
+
18 C9
C10 C11
(AG)
9
DV
R9
R10
27
SOUT
24
RIN
4
SYNC
5
SCK
Line input
R7
8
VDD
1
SGC
AG
C5
R6
14
DOUT2
11
DIN2
DOUT1
DIN1
XSYNC
RSYNC
BCLK
A/m
PDN
CHP
DG
DV
R5
24
AIN2
23
GSX2
2
AOUT2
21
AIN1
22 GSX1
4
AOUT1
DV
1
2
3
19
17
10
11
21
13 C4
14
7
15
23
27
SOUT
24
RIN
1
2
3
19
17
10
11
21
C8 13
14
7
15
23
NLP
HCL
ADP
ATT
GC
HD
(m / A)
(TEST)
VDD(P)
VSS(P)
VSS
VSS
VSS
C2
C6
C3
C7
C1=1 mF
C2=10 mF
C3=0.1 mF
C4=0.1 mF
R8
25
SIN
26
ROUT
DV
DV
DV
For cancelation of line echo
MSM7603/7603B
R5=20 kW
R6=20 kW
R7=2.2 kW
R8=10 kW
R10=10 kW
4
SYNC
5
SCK
16
SYNCO
18
SCKO
9
PWDWN
8
RST
12
CLKIN
6
VDD
VDD 20
VDD 28
DV
+
C5=1 mF
C6=10 mF
C7=0.1 mF
C8=0.1 mF
C9=0.1 mF
C10=10 mF
C11=0.1 mF
Use the MSM7704-01GS-VK as a PCM CODEC when VDD 3 V is used.
The MSM7533 is pin compatible with the MSM7704.
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¡ Semiconductor
MSM7603/7603B
NOTES ON USE
1. Set echo return loss (ERL) to be attenuated. If the echo return loss is set to be
amplified, the echo cannot be eliminated.
Refer to the characteristics diagram for E. R. L. vs. echo attenuation quantity.
2. Set the level of the analog input so that the PCM codec does not overflow.
3. The recommended input level is –10 to –20 dBm0. Refer to the characteristics
diagram for the RIN input level vs. echo attenuation quantity.
4. Applying the tone signal to this echo canceler for long duration may decrease echo
attenuation.
When used with the HD pin "L" (howling detector ON), this echo canceler may
operate faultily if, while a signal is input to the RIN pin, a tone signal with a higher
level than the signal being input to RIN is input to the SIN pin.
A signal should therefore be input either to the RIN pin or to the SIN pin. If,
however, the tone signal is input to the SIN pin while a signal is input to the RIN pin,
the ADP, HD, or HCL pin must be set to "H".
5. For changes in the echo path (retransmit, circuit switching during transmission,
and so on), convergence may be difficult.
Perform a reset to make it converge.
If the state of the echo path changes after a reset, convergence may again be difficult.
In cases such as a change in the echo path, perform a reset each time.
6. When turning the power ON, set the PWDWN pin to "1" and input the basic clock
simultaneously with power ON.
If the device is put into power down mode immediately after power ON, be sure
to input 10 or more clocks of the basic clock before setting to the power down mode.
7. After power ON, be sure to reset the device.
8. After the power down mode is released (when PWDWN pin is changed to a "1" from
a "0"), be sure to reset the device.
9. If this canceler is used to cancel acoustic echoes, an echo attenuation may be less
than 30 dB.
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¡ Semiconductor
MSM7603/7603B
EXPLANATION OF TERMS
Attenuating Function :
This function prevents howling and controls the noise level with
the attenuator for the RIN input and SOUT output. Refer to the
explanation of pins (ATT pin).
Echo Attenuation :
If there is talking (input only to RIN) in the path of a rising echo
arises, the echo attenuation refers to the difference in the echo
return loss (canceled amount) when the echo canceler is not used
and when it is used.
Echo attenuation = (SOUT level during through mode operation)
– (SOUT level during echo canceler operation) [dB]
Echo Delay Time :
This is the time from when the signal is output from ROUT until it
returns to SIN as an echo.
Acoustic Echo :
When using a hands-free phone, for example, the signal output
from the speaker echoes and is input again to the microphone. The
return signal is referred to as acoustic echo.
Telephone Line Echo :
This is a signal which is delayed midway in a telephone line and
returns as an echo, due to reasons such as a hybrid impedance
mismatch.
Gain Control Function :
This function prevents howling and controls the sound level by
with a gain controller for the RIN input. Refer to the explanation
of pins (GC pin).
Center Clipping Function : This function forces the SOUT output to a minimum value when
the signal is below –57 dBm0. Refer to the explanation of pins (NLP
pin).
Double Talk Detection :
Double talk refers to a state in which the SIN and RIN signals are
input simultaneously. In a double talk state, a signal other than the
echo signal which is to be canceled can be input to the SIN input,
resulting in malfunction.
The double talk detector prevents such malfunction of the canceler.
Howling Detection :
This is the oscillating state caused by the acoustic coupling between
the loud speaker and the microphone during hands-free talking.
Howling not only interferes with talking, but can also cause
malfunction of the echo canceler.
The howling detector prevents such malfunction and howling.
Echo Return Loss (ERL) :
When the signal output from ROUT returns to SIN as an echo, ERL
refers to how much loss there is in the signal level during ROUT.
ERL = (ROUT level) – (SIN level of the ROUT signal which returns
as an echo) [dB]
If ERL is positive (ROUT > SIN), acts as an attenuator.
If ERL is negative (ROUT < SIN), acts as an amplifier.
PHS :
Personal Handyphone System
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¡ Semiconductor
MSM7603/7603B
PACKAGE DIMENSIONS
(Unit : mm)
SSOP28-P-485-0.65-K
Mirror finish
Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)
Epoxy resin
42 alloy
Solder plating
5 mm or more
0.39 TYP.
Notes for Mounting the Surface Mount Type Package
The SOP, QFP, TSOP, SOJ, QFJ (PLCC), SHP and BGA are surface mount type packages, which
are very susceptible to heat in reflow mounting and humidity absorbed in storage.
Therefore, before you perform reflow mounting, contact Oki’s responsible sales person for the
product name, package name, pin number, package code and desired mounting conditions
(reflow method, temperature and times).
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