Kenwood TS-440S Service Manual page 23

1 3 . Band information generatio n circuit (in the RF
u n it )
B a n d information from the control u n it i s sent t o c o n n ector
1 5 of the RF u nit. Band informati o n sig n a l s BO to B3 form
a B C D code in which BO corre s p o n d s to LSB .
( M74LS 1 4 5P) is used to convert d ata from BCD to DEC, and
it g e n e rates control sig n a l s for ten of the 1 1 b a n d s . C o ntrol
s i g n a l s for the remaining band ( 2 5 . 5 MHz to 30 MHz) are
g e n e rated in the AND c i r c uit c o n s istin g of D 57, D 5 8, and
046. These contorl sig nals go through the cu rrent buffer con­
sisting of 04 1 to 04 5 ( M 5 4 56 1 P a n d 2SA 56 2Y), a n d are
OR' ed by diodes, as req uired, a n d sent to AT u nit, f i lter u n it,
CO, a n d ANT B PF, as sho w n in Fig u re 2 1 .
M 74 L S 1 4 5 P
0 40
2
7 6
04 1 M 5 4 5 6 1 P
r r
r o
0
0
0
CIRCUIT DESCRIPTION
04D
8 V
8 3 8 2 8 1 80
4 3
2 r
LSB
M S B
"
1 2 14 r s
B C D - DEC
3 4 5 6 7 9 ro
"'
"' I
I
"' I
.
w
.:
w
.
N
5 4 3 2 r
B u f f
?
• 7
042 0 4 3
"
1 2 14 1 5 16
I "'
I
.
.:
w
.
w
N
To
R F U B P F
Fig . 2 1 Band information generation c ircuit
B a n d information 7 8 0 0 P B o - 3 , B 3 B 2 B 1 B o
-
3 0 k H z
-
0 . 5 M H z
-
1 . 6 M H z
-
2 . 5 M H z
-
4 M H z
-
6 M H z
-
7 . 5 M H z
-
1 0 . 5 M H z
-
1 4 . 5 M H z
-
2 2 M H z
-
2 5 . 5 M H z
1 4V
R l 8 3
r r
2 2 8 T 1 2 5 . 5 - 30 1
I
2 4 T ( 2 2 "' 2 5 . 5 )
"'
2 1 T ( 1 4 , 5 .... . 2 2 )
I
1 4 T ( 10 . 5 - 14 . 5 )
IOT
7 T 1 6
0 4 4
G)
D 6 1
r 2 8 F 1 22 - 3 0 )
D 6 5
2 2 I F 1 1 4 . 5 - 22 1
3 1 4 F ( 7.5 - 14.51
4 7F 1 4 .... .. 7. 5 1
5
4F ( 2 . 5 "" 4 J
D62
6 ( 1 .6 - 2 . 5 )
2 F
2 1
I
O I B
I 2 2
:
I
I
I
I
L
0 2 0
024
-
_ _ .... .J
D 6 7
VCO SW VCO
0 . 5 M H z 0 0 0 0
1 . 6 M H z 0 0 0 1
2 . 5 M H z 0 0 1 0
4 M H z 0 0 1 1
6 M H z
0 1 0 0
7 . 5 M H z 0 1 0 1
1 0 . 5 M H z 0 1 1 0
1 4 . 5 M H z 0 1 1 1
2 2 M H z 1 0 0 0
2 5 . 5 M H z 1 0 0 1
3 0 M H z 1 0 1 0
Table 1 3
To AT u
7.5 ,... . JO . S J
.... .. 7. 5 )
T o Fi lie r u
{
67. 0 5 - 75.05
{
1 2 2 ...., 30 1
59. 5 5 .... . 67.05
{
( 1 4 . 5 - 2 2 )
_
52.55 59.ss
{
{ 7 , 5 - 1 4 .5 )
45.05 - 52.55
(0 "-' 7. 5 1
TS-440S
2 3