Furuno FS-1570, Service Manual

Page: 133 / 322

5.3 T-CPU board (05P0732)
5-16
TX/
RX
Pin No.
& Name
Order of
execution
Signal name Function
#16 Q1 49 TX Generates TX signal (+12 V)
#15 Q2 50 RX Generates RX signal (+12 V)
#14 Q3 51 N J3E
#13 Q4 52 N H3E
Switches between J3E and
H3E demodulators
#12 Q5 53 N.C
#11 Q6 54 N:Narrw (FL4: 450 Hz)
#10 Q7 55 M: Middle (FIL3: 2.4 k)
U7
#9 Q8 56 W: Wide (FIL2: 6 k)
Selects bandwidth of IF filter
(455 kHz)
#16 Q1 57 AGC FAST Sets AGC decay time to FAST
#15 Q2 58 N.B CONT
Switches on/off Noise Blanker
(U16)
#14 Q3 59 AGC OFF Sets AGC to OFF
#13 Q4 60 TX H3E
Adds carrier signal at H3E
transmission
#12 Q5 61 A
#11 Q6 62 B
#10 Q7 63 C
U8
#9 Q8 64 INH
Selects following check
signals connected to U9.
1) S, RX AF CHK, TX AF
CHK and TX OUT CHK
from TX/RX (05P0733)
2) TEMP from REF OSC
(05P0747)
U43 #5 PLL data PLL data for PLL IC (U43)
U42 #8 1DDS data DDS data for DDS IC (U42)
U45 #8 2DDS data DDS data for DDS IC (U45)
#16 Q1 17 BAND-1
Selects PLL Band, 100 kHz to
6 MHz
#15 Q2 18 BAND-2
Selects PLL Band, 6 to 13.5
MHz
#14 Q3 18 BAND-3
Selects PLL Band, 13.5 to
21.5MHz
#13 Q4 20 BAND-4
Selects PLL Ban, 21.5 to 30
MHz
#12 Q5 21 H/L
Divides each PLL band into
two bands
#11 Q6 22 N.C
#10 Q7 23 N.C
U44
#9 Q8 24 TEST
Outputs receiver self-test
signal (18 MHz)