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..
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The start circuit
of
the
JRL~2000F
consists of transistors TR21 0 to TR212 and periph-
eral parts.
When the
PAswitch
on the front panel is turned on, the VPA ON CONT signal
. changes from High to Low Ievei and the collector voltage of TR21 0 increases. ·
This voltage turns on TR211 via the time-constant circuit and also turns
on
the relay
K1
of the CBB-13 power
facton~o-rrector.
TR21
1 also turns on TR212 and activates
IC201
by providing it with a DC power supply.
2.3.4 CFR-1 02 Noise Filter
The CFR-1 02 noise filter is attached inside of the power supply unit.
The noise filter circuit is composed of an L-C circuit and it prevents the switching noise
component generated inside
of
the power supply unit from leaking out.
2.4 CFG-111 Matehing Circuit
The CFG-111 matehing circuit is attached to the upper part
of
the main chassis.
lt attenuates the unwanted harmonics components contained in the output
of
the
power amplifier and matches the antenna impedance to 50 ohms.
The matehing circuit consists of an RF matehing circuit,
an
impedance detector circuit,
a relay drive circuit and an output power detector circuit.
The bleck diagram is shown in Fig.4.
CONTROL CIRCUIT
Fig.4 Block Diagram CFG-111 Matehing Circuit
(1
)RF Matehing Circuit
This circuit consists of inductors and capacitors which are binary-combined
by
relay
contacts, forming an L-7t-L low pass filter as shown in Fig.S.
Each relay is controlled by the control program and activated
by
CPU intructions.
12
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