Kenwood TS-2000, Service Manual

Page: 21 / 171

21
TS-2000/X
DET
VSF
VSR
430ANT X57-606
(43RX)
Q905
Final (X45-360 B/2)
Q903 Q902 Q901
D6
X57-606
■
Progressive wave and reflected wave output circuits
The signal is detected by L7, D3 and D4. A voltage out-
put corresponding to the progressive wave and reflected
wave is produced by synthesizing the magnetically com-
bined component by L7 with the corrected electrostatically
combined component by TC1 and C9 and detecting the re-
sulting signal.
It is adjusted by TC1 so that the reflected wave voltage
under a 50
Ω
load is minimized. VR1 adjusts the frequency
characteristics in the 50MHz band.
These outputs are synthesized with detected output of
the 144MHz band and are fed to the TX-RX1 unit (X57-605).
■
Antenna turner detection circuit
The passing current is converted to voltage by L9, and
the voltage is stepped down and detected by L10. One of
these components is buffered by Q1 and Q2 and rectified by
Q3 and Q4, are input to the phase comparator (IC2) . The IC
determines the IC2 Q output “H” or “L” according to the
phase difference with a D-flip-flop. The other component is
detected by diodes (D10 and D11) and the amplitude differ-
ence is compared with the comparator (IC1).
The capacitor capacitance on the input side is changed
according to the phase difference detection output, and the
capacitor capacitance on the output side is changed accord-
ing to the amplitude difference detection output.
■
UHF final unit (X45-360 B/2)
The 430MHz band transmit signal output from the TX-
RX2 unit (X57-606) is amplified to 50W by four amplifiers
(Q901, 902, 903 and 905). The final unit consists of single
amplifiers Q901, 902, 903 and 905. The input and output of
the final stage is composed of micro-strip lines. The pro-
gressive wave and reflected wave detection circuit is also
made of micro-strip lines and used for power control and
reflected wave protection.
LPF
1.8MHz
3.5MHz
7MHz
10MHz : E
14MHz : E, 10&14MHz : K
21MHz
28MHz
50MHz
AT
–12dB
TX
RX
L10 L9
CK
D
Q
IN–
IN+
Q1 Q3
Q2 Q4
1
1
3
2
D10
D11
IC2
IC1
Q
output
L7
Filter (X51-315)
HF RX ANT
ATT
X57-605
ANT1 ANT2
Q6,7
X45-360
(A/2)
VSR
VSF
X57-605
C9
VR1
TC1
D4 D3
L6
L8
1.2GHz Unit Transmitter Section
The 10.595MHz transmit signal from 12TIF is amplified in
the sending IF amplifier (Q304). This signal is input into the
sending mixer (Q1 and Q2).
The 135.395MHz signal converted in Q1 and 2 passes
through the MCF (XF2) and IF amplifier (Q3), is input into the
diode mixer (D1) and converted to 1240~1300MHz. This
signal is amplified to approximately 0dB in the sending RF
amplifier (IC1 and Q5), then input to IC2.
It is amplified to approximately 1W in the drive power
module (IC2) and to approximately 10W in the final power
module (IC3), then sent to the antenna terminal (12ANT).
D1 Q3 Q304
XF2
135.395
MHz
Q1,2
D10
1104~
1165MHz 124.800
MHz
Q15
TX-RX 3 (X57-607)
D8
10.695
MHz
Q48
12TIF
X57-605
12ANT
D5 IC3
IC2 IC1 Q5
L12 L10
1240~
1300MHz 1240~
1300MHz
Fig. 16
Fig. 17
Fig. 18
CIRCUIT DESCRIPTION