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(3) Data Reception Circuit
The RX Data circuit consists of the HPF, LPF and Data Amp.
The received RX data is output to pin 56 of IC1 as the audio signal. The data frequency is digital signal of
600~2000 Hz. The data signal output from pin 1 of CN1 is output from pin 5 as signal of 100~4000 Hz through the
HPF of pins 35 and 36 and the LPF in IC1. And then it is amplified in the data amplifier of pins 3 and 4 and
detected after it is sent to pin 21 of the CPU.
R116
CN1
C20
1
Audio
Signal
C74
VR1
C202
C64
(4) Ringer Circuit
When the Ring signal is received with the power switch of the portable unit ON, the ringer is activated. When
the ring signal is received, pin 33 is set to High. After Q11 is turned ON, Q13 is switched on by the ringer fre-
quency in pin 30 and then the buzzer is ON.
(5) Reception Signal Circuit
The reception circuit consists of the DET amplifier, and IC1's HPF, LPF, Expander and SP amplifier.
The received voice signal is output to pin 34 as an audio signal of 200-2400 Hz via the HPF and LPF of IC1
to eliminate unnecessary elements, after it is amplified the same way for the RX data.
The amplified received voice signal is input to the expander from pin 33 because it is the demodulated signal
compressed in the base unit. The expanded signal is output to pin 30 and it is amplified by the SP amplifier of
pins 29 and 30, and sent to the SP.
The transistor Q1 for SP muting functions when it is set to ON while the SP is on. If SP muting mode is se-
lected, Q1 functions when it is set to OFF. Therefore, the CPU controls pin 47 when HIGH is output with the
SP on, and LOW is output during muting mode.
R118
R116
CN1
C20
C63
C5
1
C74
R3
VR1
C64
Q15
R117
DET Amp.
Circuit Diagram
36
R118
R5
C63
C5
35
C6
R3
Q15
R117
Circuit Diagram
Ringer Driver
R104
Q13
+
C62
–
30
CPU
ALM
Circuit Diagram
HPF
R5
36
3rd LPF
–
C6
+
35
(IC1)
HPF (100 Hz)
3rd LPF
–
5
+
fc=4 kHz
R106
Q11
R108
33
CPU
VOL1
(IC1)
R166 C7
34
33
EXP
R167
32
31
+
+
C8
C9
–
–
| 181 |
KX-F910BX
DATA Amp.
+
C37 R29
3
4
–
R30
BZR
SP Amp.
C10 VR3
–
30
29
@
28
+
R15
47
CPU SP Mute
CPU
21 pin
C1
–
+
Q1
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