Circuit Description Of Liu Pwb - Sharp FO-CC500 Service Manual

FO-CC500A
FO-K01A

[3] Circuit description of LIU PWB

(1) LIU block operational description
1) Block diagram
CONTROL PWB
IC12A
LIU PWB
IC101
2904
IC12B
HS RECEIVER
TEL MUTE
IC102
2904
IC101
2904
HS MIC
MIC MUTE
Q102
IC102
CML
IC12D
2904
LINE
CI
SPEAKER
2) Circuit description
The LIU PWB is composed of the following 6 blocks.
1. Speech circuit section
2. Dial transmission section
3. Speaker amplifier section
4. Ringer circuit section
5. CI detection circuit
6. Signal/DTMF transmission level & receiving level
CORDLESS
DSSIN
DTMF MUTE
RCVOL
1 0
0 1
IC10A IC10B
IC10C
1
0
DSSIN
RLYCONT
IC11
SIG MUTE
W-TONE
IC4
SP MUTE
IC7 IC5
2113 4051
VOLA
CML
VOLB
CI
VOLC
PWB
IC1:20438 IC2:MERLIN
DSSIN
INCOM
DSSOUT
AUDIOIN 1 GN
ADC GN
MICIN
PRE
ADC
SCALER
LINEIN GN
PRESCALE
C
SETTING
ECHOATTN
SIDE TONE 1 GN
DAC GN
DAC
F F
SPKOP
RF AUDIOIN 1 GN
TXCTRL VOLUME 1
SPKROUT GN
LINE ATTN
LINE
GPIO
RX AMP(MIC AMP)
MIC ENABLE
0,20,25,30dB 0dB
MIC GAIN LININ GAIN
SIGRX MICP
GAIN LPF
TELOUT LINEIN
LINE IN ENABLE
SPEAKER
OUT ENABLE
1,0
TX AMP
0,1
SP
0,0
DRIVER
SIGTX
SPKRP
1,1
RT LOOP
LINE OUT
ENABLE 0,0
SP AMP
1,0
LINE
1,1
DRIVER
LINEOUT
LNINSEL
MUTE,0,–6,–12dB
LINE OUT ATTENUATION
TONE
TEL MUTE SP MUTE VOLA
CML
RCVOL SIG MUTE VOLB
CI
DTMF MUTE W-TONE VOLC
Fig. 5
3) Block description
1. Speech circuit section
•
This circuit is composed by IC101.IC102 and that circumference
circuit.
2. Dial transmission section
•
D.P. transmission: The CML relay is turned on and off for control in
the DP calling system. (Refer to the attached sheet.)
•
DTMF transmission: It is formed in the modem, and is output.
3. Speaker amplifier section
•
Ringer volume
•
Speaker volume :It is controlled by the attenuator value of the
4. Ringer circuit section
•
The ringer sound is formed in the tone of modem when CI signal is
detected. The amplifier circuit drives the speaker of the main body.
5 – 10
IC5:MERLIN
ADC GN
AUDIOIN 1 GN
ADC
SIDE TONE 1 GN
POSTSCALE
SETTING
DAC GN
POST
F
DAC
SCALER
TXCTRL
RF AUDIOIN 1 GN
VOLUME 1
TG1, TG1,
TG2 TG2
LINE ATTEN
AUX VOLUME
TG3
ADC
0,–4dB
ADC GAIN
DAC
0,6dB
DAC GAIN
MIC MUTE
RLYCONT SASTXD,SASRXD
IC3:SCE214V
:It is controlled by the combination of the
attenuator value of the LINE DRIVER in the
modem and the ringer sending level sent from
the modem.
IC5 and IC3 (VOL-A,B,C)
CORDLESS
HANDSET PWB
IC8:20438
MIC IN
MIC
MIC GN
LINEIN GN
SPKOP
F
RECEIVER
SPKR OUT GN
EMJMIC
IC7
EMJSP
LINE O
EMJSP AMP
EMJSP MUTE
IC5:MERLIN
IC6
AUXDAC
SPEAKER
SP MUTE SP MUTE
EMJSP MUTE