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KX-F910BX
(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).
IC201
1
NC
MixR
2
TXO
MixIN
(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.
VRX
R235
VRX
3
C219
AF
1
GND
2
Circuit Diagram
C240
24
23
C241
Circuit Diagram
+
-
C223
R215
R214
R213
9
10
11
12
13
14
+
-
DET
IF
8
7
6
5
4
3
F202
TX
R230
R228
F204
R229
L204
R231
Q204
C224
R217
R218
15
16
Q201
MIX
OSC
2
1
C232
|176 |
ANT
L209
C257
12
GND
MixO
13
IC201
VRX
R220
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