-
.j
--J
!
(3)SWR Detector Circuit
Vf and Vr detected by the outputpower detectorcircuit of CFG-111 are compared by
comparator IC15. ·
When the VSWR value which is a ratio of Vf to Vr, exceeds 3.5, No.4 pin of IC15
becomes Low Ievei to inform CPU of the
SW_R
alarm (A8).
On the other hand, Vf and Vr are applied to the SWR operating circuit made up of
IC14, IC17 and peripheral parts. The calculated SWR is indicated in the voltmeter
on
the front panel.
The circuit made up of IC15, CD6, R54, R55 and C67 holds the peak of Vf.
Data selector
IC
of
IC1
0 selects signals which are connected to the front panel meter.
Camparator IC16 which has an outputterminal (No.8 pin) compares Vf with the refer-
ence voltage adjusted by the variable resistor RV1. lf Vf exceeds the reference volt-
age,
an
ALC voltage
is
generated.
The ALC voltage moves the pointer of the voltmeter via diode CD5 and it is inversely
amplified to a negative voltage by IC17 oparational amplyfier and then sent to the
exciter.
(4)Frequency Measurement Circuit
The
RF
signal from the exciter, which is detected by the CSC-433 antenna switch
circuit, is applied to
J41
0,
and
is
then amplified by transistor TR2.
The signal
is
wave-shaped to the reetangular
Wave
by the IC23 two-stage buffer
amplifier.
After the divider of
IC11
divides this signal ten times, it
is
applied to the timer
IC
of
IC4.
IC4
is
controlled by CPU and measures frequency of the exciter output signal by
counting this signal.
2. 7 Automatie Tuning
The CDJ-1143 control CPU of the JRL-2000F automatically tunes the antenna by
controlling relays of the CFG-111 matehing circuit according
to
the program written to
ROM1. ,
SET and TUNE operations will be described here.
(1
)SET
When the SET switch is pressed,
No.11
pin (SELBK) of the CDJ-1143 control J3
changes to Low Ievei and requires power from the exciter.
17
Downloaded
by
RadioManuai.EU
To Next Page
Loading...