Kenwood TS-830S Service Manual page 46

SPECIFICATIONS
Oscillation frequency
...
Output voltage
.............
Frequency stability
.......
5.40
-
6.10 MHz
0.2V
t;
dB
Escutcheon glass
(81 0-0632-04)
1
Knob 6
Knob 1
(K29-0738-04) Knob (K23-0738-04) Case (upper)
(K29-0726-04)
I
/A01 -0786-03)
-0635-1 4)
1
Within
+
1 x 1 0
'
at 0
-
50°C
F~~~~
within f 3 x 1 0
'
at room temp.
(B1 O'
Power consumption
.....
Power requirement
......
AC 120V 50/60Hz (in U.S.A.)
AC 220V/240V (Selectable)
50/60Hz
( ~ n
Europe)
CPU LSI
. . . . . . . . . . . . . . . . . . . .
1
Case (lower)
'
(A01 -0787- 12)
Semiconductors used
...
Push knob (A)
(K27-0422-04)
FET
............................
1
I
Push knob (B)
(K27-0423-04)
Transistors
. . . . . . . . . . . . . . . .
55
I
Push knob ( C )
(K27-0424-04)
Knob
(K29-07 1 6-04)
Dimensions
.................
Foot
,
, A - A n . -
.
A ,
I
IJUL-UU4Y- 1 4 1
Round boss
(Figures in ( ) include projections.)
I
Hex. head screw
I
(N39-0306-04) Dial scale
(820-08 1 6-04)
Weight
........................
Approx. 3 kg (6.61 Lbs.)
I
Panel
CIRCUIT CONFIGURA'TION
The VFO-230 consists of a double PLL l o o p the 1 st loop However, it is supplied from the orystal oscillator ( Q 2 ) for RIT
covering a 2 0 kHz bandwldth at 2 0 Hz step, and the 2nd loop operation or CW transmission. When the RIT feature is ON.
covering a 7 0 0 kHz
bandwidth
at 2 0 kHz step. the voltage applled across the varicap diode in the crystal
As the tuning dial is turned. an optical encoder
(using
a photo
sensor) converts the dial rotatlon and ~ t s direction of rotation
into an electrical s~gnal, which
IS
coupled to
microprocessor
lC 1 1 (pPD8048C- 1 5 5 )
The microprocessor internally processes this dial signal and
outputs the processed result as f r e q u e n c y - d ~ v ~ s ~ o n data for
the PLL and, at the same time, provides the corresponding
dial display data
In the 1 st PLL loop, MIXER-1 (IC14 pPC1037H) combines
the output of VCO-1 (Q42, 4 3 ) at 1 4 - 1 7 9 9 8 MHz with a
oscillator
IS
varied by the RIT control to obtain a frequency
variation range ~f k g 0 0 Hz. During CW transmission, the
voltage across the varicap diode
IS
adjusted by variable
resistor VR 1 on the d i g ~ t a l unit t o provide this oscillator with
an output frequency 8 0 0 Hz higher than its original
frequency The output of MIX-3 goes through a band-pass
fllter (T2. T3, T4), and then couples to a fourth mixer, MIX-4
(IC-26). Here
~t
IS
mixed with the output of VCO-2
( 5 . 4 - 6 . 0 9 9 9 8 MHz) and is converted to 8 8 0 - 1 5 6 0 kHz.
This output, after amplification, is coupled to Programmable
1 0 MHz reference frequency to convert the output to
4 . 0 - 7 9 9 6 MHz. This output is ampllfled and coupled to
P r o g r a m m a b l e D ~ v l d e r 1 ( I C 1 2 ) , w h e r e ~t i s
frequency-divided according to the division data from the
microprocessor into a 2 kHz s~gnal
The phase of this 2 kHz signal
IS
compared with that of the
reference 2 kHz signal by phase comparator PD-1 (llC13).
and this output
I S
fed back to control the output frequency of
VC 0- 1
The 4 - 7 9 9 8 MHz signal (at 4 kHz steps) generated in the
1 st PLL loop is further frequency-dlvided by a 1 / 1 0 0 (IC1 5,
1 6 ) and 1/2 (IC6 1/21 divider into a 2 0 - 3 9 . 9 8 kHz signal
(at a 2 0 Hz step) Thls signal is coupled t o MIXER-2 (IC25).
where it is mixed with a reference 5 0 0 kHz signal whlch
converts the signal to 4 8 0 - 4 6 0 . 0 2 kHz. The output of the
Divider 2 where ~t is frequency-divided to an output
frequency of 2 0 kHz according to the division data supplied
from the microprocessor. This output goes to phase detector
PD-2 (IC24). where its phase is compared with the 2 0 kHz
reference signal to create the frequency con-trol signal for
VCO-2
All the circuits hitherto described are always operating.
However, the digital VFO provides its output intermittently t o
control the buffer amplifier. When the VFO in the main unit is
operating, this VFO output is mixed with a 5 MHz reference
slgnal by MIX-5 (Q5). of which output at 4 0 0 kHz t o
1 0 9 9 . 9 8 kHz is amplified, then counted up by a 6-digit
frequency counter (IC8) The output data of this counter is
stored Into the microprocessor's memory.
As seen above, all frequencies except the RIT and CW
second mixer goes through a narrow-band ceramic filter transm~ssion shift frequencies are composed of combi-
( C F l ) , then couples to a third mixer, MIX-3 (IC27), where it
IS
nations of reference frequencies. As a result, the accuracy
further mixed w ~ t h a 5 MHz signal The signal
IS
now and stability of the digital VFO output frequency is identical t o
converted to 4 5 2 0 - 4 5 3 9 . 9 8 kHz. A reference 5 MHz s ~ g -
that of the 1 0 MHz reference oscillator.
nal is usually used for the other Input of this t h ~ r d mixer