Panasonic KX-TCD540RUM / KX-TCA154RUM / KX-TCD540RUT / KX-TCA154RUT Service Manual ▷ View online
20 BLOCK DIAGRAM (BASE UNIT)
KX-TCD540RUM/RUT BLOCK DIAGRAM (BASE UNIT)
TEL Jack
Hook
Q4,Q5
IC2
SC14429
DC Jack
EARTH
(option)
Regulator
4.0V
IC1
Regulator
3.2V
Q2
Regulator
4.0V
IC14
Regulator
1.8V
Q3
74VHC574
(D_FF)
IC12
74VHC574
(D_FF)
IC13
Key
LCD
Hook-SW
SW531
LED
RF
Module
Flash
(4M)
IC7
EEPROM
(128K)
IC3
SP AMP
IC10
Handset
Jack
Hook-SW
A0
SCL
SI
A0
SCL
SI
RESn
CS
COL[4-0]
LED 3
LED 5
LED 2
4.0V
3.2V
SK
SO
LE
PD2
RFCLK
RDI
PD3
TDO
RSSI
PD1
PD5
LINE OUT
LINE_IN-
ADC0-
P2[7]
LINE_IN-
ADC0-
P2[7]
CIDIN+
CIDIN-
ADC1
ADC2
CIDIN-
ADC1
ADC2
CIDOUT
RINGING
AVD
VDD
RINGING
AVD
VDD
LDO2_CTRL
VDDIO
LDO1_SENSE
LDO1_CTRL
VDDIO
LDO1_SENSE
LDO1_CTRL
CAP
VDDRF
VSSRF
Xtal
JTIO
URX
UTX
P1[4]
P3[7]
SCL1
SDA1
P0[7-3]
P1[4]
P3[7]
SCL1
SDA1
P0[7-3]
DAB[15-0]
LSR+
P3[1]
MIC+
LSR-
MIC-
SCL2
SDA2
RDn
WRn
ACS0
AD[18-1]
ACS1
P1[0]
P1[1]
P3[6]
P1[5]
P1[1]
P3[6]
P1[5]
ACS2
OE
WE
CE
A[17-0]
WE
CE
A[17-0]
DQ[15-0]
VCC_PA
VCC_OC
VCC_OC
RF1
SYCL
SYDA
SYEN
RXDSG
SYRI
RXDA
PAON
TXDA
RSSI
SYDA
SYEN
RXDSG
SYRI
RXDA
PAON
TXDA
RSSI
10.368MHz
OPERATION
MAIN
A
B
OP AMP
IC15
TAM
Flash
Flash
(64M)
IC6
OR gate
IC8
REn
WEn
ALE
CLE
CEn
CLE
CEn
R/Bn
I/O[7-0]
Diode Bridge
D3
ROW[5-0]
4.0V (B)
4.0V (B)
4.0V (A)
Serial Pin
Xtal
CN9
CN501
BBIC
Pin Diode
DA1
SP
MIC
PSTN I/F
(Public Switched
Telephone Network Interface)
Telephone Network Interface)
NSA
(option)
P2[1]
P2[0]
P2[6]
DC Impedance/
AC Impedance
AC Impedance
(option)
K
X
-T
C
D
5
40R
U
M
/
/
K
X-
T
T
C
A
154R
U
M
/
/
K
X-
T
T
C
D
540
R
U
T
/
/
K
X-
T
T
C
A
154R
U
T
81
21 CIRCUIT OPERATION (BASE UNIT)
21.1. Outline
Base Unit consists of the following ICs as shown in BLOCK DIAGRAM (BASE UNIT) (P.81).
•
•
•
•
DECT BBIC (Base Band IC): IC2
−
−
−
−
Handling all the audio, signal and data processing needed in a DECT base unit
−
−
−
−
Controlling the DECT specific physical layer and radio section (Burst Module Controller section)
−
−
−
−
ADPCM codec filter for speech encoding and speech decoding (DSP section)
−
−
−
−
Echo-cancellation and Echo-suppression (DSP section)
−
−
−
−
Any tones (tone, sidetone, ringing tone, etc.) generation (DSP section)
−
−
−
−
DTMF receiver (DSP section)
−
−
−
−
Clock Generation for RF Module
−
−
−
−
ADC, DAC, timer, and power control circuitry
−
−
−
−
All interfaces (ex: RF module, EEPROM, LED, Analog Front End, etc.)
•
•
•
•
RF Module: RFM1
−
−
−
−
PLL Oscillator
−
−
−
−
Detector
−
−
−
−
Compress/Expander
−
−
−
−
First/Second Mixer
−
−
−
−
Amplifier for transmission and reception
•
•
•
•
FLASH MEMORY: IC6
−
−
−
−
Voice Prompt (TAM) D/L (DownLoad) Area
•
•
•
•
FLASH MEMORY: IC7
−
−
−
−
Program D/L (DownLoad) Area
•
•
•
•
EEPROM: IC3
−
−
−
−
Temporary operating parameters (for RF, etc.)
Refer to EEPROM LAYOUT (BASE UNIT) (P.94).
•
•
•
•
Additionally,
−
−
−
−
Power Supply Circuit (+4.0V, +4.0V, +3.2V, +1.8V output)
−
−
−
−
Crystal Circuit (10.368MHz)
−
−
−
−
Telephone Line Interface Circuit
−
−
−
−
SP Phone Circuit
−
−
−
−
Curl Cord Handset Interface Circuit
82
KX-TCD540RUM / KX-TCA154RUM / KX-TCD540RUT / KX-TCA154RUT
21.2. Power Supply Circuit
The power is supplied to the DECT BBIC, RF Module, EEPROM, SP AMP, LED from AC Adaptor (+6V) as shown in Fig.101.
The power supply is as follows;
The power supply is as follows;
•
•
•
•
DECT BBIC (IC2): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
IC2
•
•
•
•
RF Module (RFM1): CN2(+6V)
→
L8
→
D1
→
IC1
→
RF Module
•
•
•
•
EEPROM (IC3): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
IC3
•
•
•
•
Flash Memory (IC7): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
IC7
•
•
•
•
SP AMP (IC10): CN2(+6V)
→
L8
→
D1
→
IC14
→
IC10
•
•
•
•
Logic IC (IC12, IC13): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
IC12, IC13
•
•
•
•
LCD (CN502): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
CN9
→
CN501
→
CN502(LCD)
•
•
•
•
LED (LED501, LED502, LED503, LED504, LED505): CN2(+6V)
→
L8
→
D1
→
IC14
→
CN9
→
CN501
→
LED
•
•
•
•
OP AMP (IC15): CN2(+6V)
→
L8
→
D1
→
IC14
→
IC15
•
•
•
•
TAM Flash Memory (IC6): CN2(+6V)
→
L8
→
D1
→
IC1
→
Q2
→
IC6
<Fig.101>
83
KX-TCD540RUM / KX-TCA154RUM / KX-TCD540RUT / KX-TCA154RUT
21.3. Telephone Line Interface
<Function>
•
•
•
•
Bell signal detection
•
•
•
•
Clip signal detection
•
•
•
•
ON/OFF hook circuit
•
•
•
•
Audio circuits
Bell & Clip (: Calling Line Identification Presentation: Caller ID) signal detection:
In the standby mode, Q4 is open to cut the DC loop current and decrease the ring load.
When ring voltage appears at the TP21 (A) and TP19 (B) leads (when the telephone rings), the signal is transferred as follows;
•
•
•
•
A
→
C13
→
R17
→
R24
→
IC2 Pin 107 (CID IN +)
•
•
•
•
B
→
C12
→
R16
→
R32
→
IC2 Pin 112 (CID IN -)
ON/OFF hook circuit:
In the standby mode, Q4 is open, and connected as to cut the DC loop current and to cut the voice signal. The unit is
consequently in an on-hook condition.
consequently in an on-hook condition.
When IC2 detects a ring signal or press SP Key or pick up Curl Cord Handset or press the TALK Key onto the handset, Q5 turns
on and then Q4 turns on, thus providing an off-hook condition (active DC current flow through the circuit) and the following
signal flow is for the loop current.
on and then Q4 turns on, thus providing an off-hook condition (active DC current flow through the circuit) and the following
signal flow is for the loop current.
•
•
•
•
A
→
D3
→
Q4
→
R34
→
Q8
→
R45
→
R46
→
D3
→
B [OFF HOOK]
21.4. Transmitter/Receiver
Base Unit and Cordless Handset mainly consist of RF Module and DECT BBIC.
Base Unit and Cordless Handset transmit/receive voice signal and data signal through the antenna on carrier frequency.
Signal Pass:
*Refer to SIGNAL ROUTE (P.88).
21.4.1. Transmitter Block
The voice signal input from the TEL LINE interface goes to RF Module (RFM1) through DECT BBIC (IC2) as shown in BLOCK
DIAGRAM (BASE UNIT) (P.81)
DIAGRAM (BASE UNIT) (P.81)
The voice signal passes through the analog part of IC2 where it is amplified and converted to a digital audio stream signal. The
burst switch controller processes this stream performing encryption and scrambling, adding the various other fields to produce
the GAP (Generic Access Profile) standard DECT frame, assigning to a time slot and channel etc.
burst switch controller processes this stream performing encryption and scrambling, adding the various other fields to produce
the GAP (Generic Access Profile) standard DECT frame, assigning to a time slot and channel etc.
In RFM1, the carrier frequency is changing, and frequency modulated RF signal is generated and amplified, and radiated from
antenna. Cordless Handset detects the voice signal or data signal in the circuit same as the following explanation of Receiver
Block.
antenna. Cordless Handset detects the voice signal or data signal in the circuit same as the following explanation of Receiver
Block.
21.4.2. Receiver Block
The signal of 19.2 MHz band (18.81792 MHz ~ 18.97344 MHz) which is input from antenna is input to RFM1 as shown in
BLOCK DIAGRAM (BASE UNIT) (P.81).
BLOCK DIAGRAM (BASE UNIT) (P.81).
In RFM1, the signal of 19.2 MHz band is downconverted to 864 kHz signal and demoduleted, and goes to IC2 as GAP (Generic
Access Profile) standard DECT frames. It passes through the decoding section burst switch controller where it separates out
the frame information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is
turned back into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.
Access Profile) standard DECT frames. It passes through the decoding section burst switch controller where it separates out
the frame information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is
turned back into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.
21.5. Pulse Dialing
During pulse dialing the hookswitch (Q4,Q5) is used to generate the pulses using the HOOK control signal, which is set high
during pulses. To force the line impedance low during the "pause" intervals between dial pulses, the PULSE_DIAL signal turns
on Q9.
during pulses. To force the line impedance low during the "pause" intervals between dial pulses, the PULSE_DIAL signal turns
on Q9.
84
KX-TCD540RUM / KX-TCA154RUM / KX-TCD540RUT / KX-TCA154RUT
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