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KX-F910BX
CIRCUIT OPERATION
(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.
Circuit Diagram
Circuit Diagram
(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.
+
R104
Ringer Driver
Q13
30
33
CPU
ALM
CPU
VOL1
R106
Q11
BZR
R108
–
C62
C20
1
VR1
C74
R116
C64
R118
C63
Q15
R117
R3
C5
C6
HPF
36
35
3rd LPF
(IC1)
R166 C7
R167
34
32
31
30
29
@
C8
C9
+
–
+
–
C10 VR3
R15
SP Amp.
28
+
–
Q1
47
CPU SP Mute
DET Amp.
+
–
R5
+
–
C1
CN1
EXP
33
Circuit Diagram
–
+
–
+
CN1
Audio
Signal
1
C20
VR1
C64
C74
R116
Q15
R118
C63
R3
C5
C6
R5
36
35
(IC1)
R117
HPF (100 Hz)
3rd LPF
fc=4 kHz
5
4
C37 R29
DATA Amp.
3
R30
CPU
21 pin
C202
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