Kenwood TR-2600A - Page 5

TR-2600A/E
CIRCUIT DESCRIPTION
RS
ATX ©
the digital codes are
During transmission, |
high.
OTXS
High during transmission
inhibit (out-of-band),
digital code indication
TC adn call sign indication.
Low in all other cases.
R68
4.7K Océ
$4 TX STOP Manual transmission is probibited (at open).
Fig. 4 Control circuit (standby) RX unit
TRANSMITTER TX UNIT (X56-1470-XX)
The voice audio signal from the microphone is amplified by
IC2 : LAG4585S located on the TX unit. Its output is used | vee0 | vee | vero | ie
to directly modulate the VCO (Voltage Controlled Oscilla-
tor) through 011 : MA856. The VCO output is amplified
by Q2 : 2SC2668(Y) and O3, further amplified by pre-
driver Q4, driver Q5 and final power amplifier Q6 :
2SC1947.
Table
7
2SC1947
Max.
rating
(TX
unit
Q6)
The VCO signal from Q3 is also amplified by Q1 and is
applied to the receiver first mixer on the RX unit as the
local oscillator signal.
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sa
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+
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Tap
Ow
20 80
Fig. 5 LAG458S Equivalent circuit (TX unit 1C2)