Circuit Description; Receiver - Alinco DJ-X3 Service Manual

CIRCUIT DESCRIPTION

1) Receiver

1. RX Method: Triple Super Heterodyne Method
1st IF. : 248.45MHz
2nd IF. : 38.85MHz
3rd IF. : 450KHz
2. Front End
0.1 ~ 29.995MHz
30 ~ 136.995MHz
137 ~ 222.995MHz
223 ~ 367.995MHz
368 ~ 469.995MHz
470 ~ 129.995 MHz
3. Mixer
The 1st Mixer
The signal input from antenna is switched at band switch D19, passing through
the low pass filter, it is amplified at RF amplifier Q15. Then the signal is added
to the 1st mixer IC3 through the band switch D17.
The signal input from antenna is switched at band switch D23, passing through
the band pass filter, it is amplified at RF amplifier Q21. Then the signal is added
to the 1st mixer IC3 through the band switch D22.
The signal input from antenna is switched at band switch D27, passing through
the band pass filter, it is amplified at RF amplifier Q23. Then the signal is added
to the 1st mixer IC3 through the band switch D26.
The signal input from antenna is switched at band switch D29, passing through
the band pass filter, it is amplified at RF amplifier Q27. Then the signal is added
to the 1st mixer IC3 through the band switch D28.
The signal input from antenna is switched at band switch D32, passing through
the band pass filter, it is amplified at RF amplifier Q32. Then the signal is added
to the 1st mixer IC3 through the band switch D31.
The signal input from antenna is switched at band switch D37 and D45,
passing through the band pass filter, it is amplified at RF amplifier Q38. Then
the signal is added to the 1st mixer IC3 through the band switch D36.
The input signal and the 1st local signal is added or subtracted at mixer IC3,
and SAW filter FL1 selects the signal of 248.45 MHz, then eliminates the
adjacent signal.
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