TS-440S
CIRCUIT DESCR I PTION
VsF
is compared with voltage from IC8 pin 6
(5.5 V).
When SWR increases,
VsF
lowers and the voltage level
of IC8 pin 8 rises. At IC7 pin 3, a tria n g u l a r wave is moni
tored. The triangular wave is compared with the wave
from IC8 pin 8 and output. The tria n g u l a r wave is con
verted to a square wave by IC 1 0 and sent to switch Q3
and 04 . This voltage is used as the SWR control voltage.
3 ) FULL/SEMI BREAK-IN and VOX circuits
STA N D-BY
SW
Output voltage from IC8 pin 2 consists of the voltage com
pared with
VsRIVsF
and
+ 5
DC voltag e. It is distributed
to IC4 the level shift/meter amplifier to move the needle
in the SWR meter and IC 5 the
V-J
convertor to control the
AT440.
VR 1 4 is used to adjust the SWR meter ZERO point .
VR 1 3 is for SWR meter adjustment
RL TXB
RXB
MI CROPROCESSOR
STAN D-BY
CONTROL
CIRCUIT
POWER SUPPLY
CON TROL
CIRCUI T
KEYI N G
CIRCUIT
M IC
vox
C I RCU IT
Fig . 9 - 1 FULL/SE M I BREAK-IN block diagram
When the standby switch, the key, or the VOX switching
transistor a re activated, a g round is applied to the in put pin
of the contro l circuit, which causes a standby sign a l to be
fed to the microprocessor to determine if a valid transmit con
dition has been met. When that condition has been met, the
JlfLJ1
KEYING
STAND-BY
vox
A
O N E SHOT
MULTI -
VIBRATOR
D
E
L
A
Y
T
I
M
E
A
sta ndby circuit in the IF u nit wil l be turned on.
A keying sig n a l is generated by the control circuit, whenever
the key is depressed, to control the keying circuits in the IF
u nit . This keying sig n a l is also used as the tra nsmit/receive
sign a l d u ring break-in operations.
KEYING CFULU
CONTROL( FULL)
Fig . 9-2 FULL/SE M I BREAK-IN timing chart
1 3