M 38267M 8L252G P (Xa0725) - Alinco DJ-493 Service Manual

6. CTCSS Encoder
7. DCS Encoder
8. CTCSS, DCS Decoder
9. Clock Shift

5) M 38267M 8L252G P (XA0725)

CPU
Terminal Connection
(TOP VIEW)
SEG12
SEG11
SEG10 -------
SEG9 ■*
SEG8 ------- [TO
SEG7
SEG6 -------
SEG5 -•----- [83
SEG4 —
SEG3
SEG2 ------- [86
SEG1
SEGO
VCC
VREF -----
AVSS ----
COM3 -•----- [92
COM2 -------
COMI -«-----
COMO -------
VL3 -----► [96
--_
VL2
C2 -----► ¡9B
C1 -----► [99
VL1 — ►
6
The CPU (IC9) is equipped with an internal tone encoder. The tone signal
(67.0 to 250.3 Hz) is output from pin 9 of the CPU to the varicap (D4) of the
The CPU (IC9) is equipped with an internal DCS code encoder. The code (023
to 754) is output from pin 9 of the CPU to the varicap (D16) of the PLL refer­
ence oscillator. When DCS is ON, DCS MUTE circuit (Q12-ON, Q18-ON, 015-
OFF) works. The modulation activates in X1 side only.
The voice band of the AF output signal from pin 10 of IC4 is cut by sharp active
filter IC7 (VCVS) and amplified, then led to pin 4 of CPU. The input signal is
compared with the programmed tone frequency code in the CPU. The squelch
will open when they match.
In the unlikely event that CPU clock noise is present on a particular operating
frequency programmed into the radio, you can shift the CPU clock frequency
to avoid the CPU clock-noise. The output signal from pin 31 of the CPU turns
on Q35. Then the oscillation frequency of X3 will be shifted about 300 ppm.
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• P21
44) - - P22
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- P23
4 2 ]- - P24
43-
• P25
40] - • P26
• P27
VSS
- XOUT
XIN
• XCOUT
34].
XCIN
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RESET
=
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P70/INTO
m -
• P71
30) -
• P72
29 - • P73
n
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• P74
27) - - P75
26) -
• P76
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