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176
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KX-F910BX
Circuit Diagram
(2) Receiver RF Circuit ( ): Portable Handset
The electric wave received from the antenna is attenuated by the SAW filter F204 except the received frequency
band.
Then it is amplified by the RF amplifier Q204 and Q203, and supplied to the IC201 pin 23 (MIXER input).
(3) MIXER IF Circuit ( ): Portable Handset
The signal in the received frequency band supplied to IC201 pin 23 (MIXER input) is converted to 21.4 MHz of
the 1st IF by the received local signal in the MIXER circuit, and output to pin 13 of MIXO. The resonance circuits
of C235, L201 and L202 are resonated to 21.4 MHz. The 21.4 MHz IF signal becomes an element of the
}
7.5
kHz band width by the MCF F201 and is supplied to IF amplifier Q201. The signal is supplied to IF IC204. The
second local frequency is 20.945MHz. The frequency is converted here into the 455kHz second IF frequency. It
is detected inside the IC204 and it appears at pin 11 as the demodulation audio signal.
Circuit Diagram
IC201
1
2
24
23
TXO
NC
MixIN
MixR
C241
C240
C247
C246
R228
Q203
L204
R230
C248
R231
Q204
F204
L212
ANT
R229
L209
L203
L205
C255
TX
C256
L214
C257
+
-
VRX
C217
C218
R216
R217
R218
R220
VRX
R219
C235
L202
L201
GND
MixO
12
13
IC201
Q201
C234
F201
1
IC204
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
C224
R215
R214
C223
R213
C232
X202
C227
C231
F202
C230
C229
C228
C226
CD201
C225
R212
R211
C219
C220
1
2
3
AF
GND
VRX
R235
C222
OSC
MIX
DET
IF
+
-
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