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NOTES
I
. REFER TO TABLE 8-102 FOR SCHEMATI
C
DIAGRAM NOTES.
20 MHz
LOW-PASS
FILTER
P/0 A3AII
FM SUM LOOP
P/0
PHASE ERROR
XA3AIO SIGNAL TO FM SUM
DN LOOP MIXER
14),
I
D
Po
24
R
L
C22
47p
V
J4
' < 3
INTEGRATED CIRCUIT
VOLTAGE AND
GROUND CONNECTIONS
REFERENCE
DESIGNATIONS
PIN
NUMBERS
UI
+5V
1,14
7
C23
loop
l
LID
680n
C24
4TP
R30
51
.1
L9
330n
+0
.3Vdc NORMALLY
IF
(Jl)
FREQUENCY ERROR SIGNAL
>20 MHz
SQUARE WAVE*
+0
.3 TO +0
.9Vdc
<20 MHz
SQUARE WAVE*
+0
.3 TO -I
.2Vdc
* RATE IS PROPORTIONAL TO
4 F OF IF SIGNAL FROM 20MHz
U4
-
1,16
+5V
-
• 8
A3AIDU3
TOP VIEW
CIRCUIT
BOARD
TOP VIEW
2.
TROUBLESHOOTING VALUES ARE TYPICAL
.
THEY ARE ACTUAL MEASURED VALUES.
YOUR MEASUREMENTS MAY BE SLIGHTLY
DIFFERENT THAN WHAT IS SHOWN.
3.
ASTERISK(*
-
) INDICATES THAT THESE
PARTS ARE SELECTED IN TEST
. THE
VALUES SHOWN ARE TYPICAL ONLY.
REFER TO SECTION V FOR PROCEDURE
4.
LOGICS FOR ECL DEVICES IN THIS
INSTRUMENT ARE NONSTANDARD DUE TO
THE SUPPLY VOLTAGE USED
.
A
HIGH
LEVEL IS >4
.OV,
A
LOW LEVEL IS <+3
.5V
REFERENCE DESIGNATIONS
NO PREFIX
A3AI0
33,52
2
CI-24
DSI
JI
LI-10
QI-5
RI-43
TPI,2
UI
4
A3AII
J2 4
TP
XA3A
IO
10
LOGIC LEVELS
ECL
(NOTE 4)
>+2V
>+4
.OV
<+0
.8V
<+3
.5V
< IS MORE NEG
. THAN
> IS MORE POS
. THAN
1AA~62
v
FM SUM LOOP
OUT-OF-LOCK
(STATUS *05)
TO DCU
TRANSISTOR AND
INTEGRATED CIRCUIT
PART NUMBERS
REFERENCE
DESIGNATIONS
1854-0345
1854-0404
1853-0007
1820-1344
0955-0095
1826-0191
1820-0803
A3AIOU2
MIXER
BOTTOM VIEW
CIRCUIT
BOARD
TOP VIEW
I
q
014
16
10
016
KEY-'O 0
•
•
KEY-
1
0 0
q
0 0 0
q
0 ' 0 0
q
0 0 0
q
0 0 0
70 08
0 0
80 09
SERVICE SHEET
2 5
A3A10
Figure 8-444
. A3A10 FM Sum Loop Phase
Detector Schematic
8-495/496
TTL
HIGH
LOW
P/0
W52
n
LOWOPEN HIGH
LOWGROUND HIGH
PART
NUMBERS
QI,3
Q2,5
Q4
UI
U2
U3
U4
BLUE
BEAD
CIRCUIT
BOARD
TOP VIEW
A3AIOU4
TOP VIEW