Circuit Description - Alinco DJ - C7 T Service Manual

CIRCUIT DESCRIPTION

1) Reception
1. RX Method
2. Front End
3. Mixer
[FM/AM]
Double Super Heterodyne Method
1st IF: 50.85MHz
2nd IF: 450kHz
[WFM]
Single Super Heterodyne Method
1st IF: 10.7MHz
[WFM BAND]
The signal input from antenna passes through the low pass filter, and then it is
amplified at RF amplifier Q13. The amplified signal is led to band pass filter
and band switch D17, then input to the mixer IC3.
[VHF BAND]
The signal input from antenna passes through the low pass filter, and then it is
amplified at RF amplifier Q18. The amplified signal is led to band pass filter
and band switch D17, then input to the mixer IC3.
[UHF BAND]
The signal input from antenna passes through the band pass filter, and then it
is amplified at RF amplifier Q21. The amplified signal is led to band pass
filter and band switch D29, then input to the mixer IC3.
[FM/AM]
The input signal to the mixer IC3 and the 1st local signal are added or
subtracted at mixer IC3, and the crystal filter FL1 selects the signal of 50.85
MHz, then it is amplified at the 1st IF amplifier Q15 after the adjacent signal
is eliminated.
[WFM]
The input signal to the mixer IC3 and the 1st local signal are added or
subtracted at mixer IC3, and the ceramic filter FL2 selects the signal of
10.7MHz, then it is amplified at the 1st IF amplifier Q14 after the adjacent
signal is eliminated.
3