Table of Contents
Advertisement
OCUBIC
COMMUNICATIONS
S,.AIII
DIVIBIDN
+5V
COUNTER TIME BASE
VIOI
1t121
1t122
The
necess~
control slggals for
the counter (clr, rst, and xfr) ,
are
generated
by
the
time
base/control
circuitry.
Crystal nOl, operating at
a frequency of
1.JI072 MHz,
provides
the stability
necessary for accurate
frequency measurement.
ClIO
permits
it
to be adjusted
to
precisely the
correct
frequency.
Ul14 contains the
oscillator circuitry, as weIl as a di-
vider with a factor of 2 14 , or 16,J84.
The output of the
counter is the squ-
are wave
signal
labelled
"clock" on
the
timing
chart.
Ul15 is a
decade
counter,
with
outputs
taken at
the
clock-divided-by-two (A) terminal, and
the clock-divided-by-ten (D) terminal.
The waveforms
are shown in
proper relationship in the timing diagram.
The
D output, inverted
by
Q105, is used as the clr signal;
gate UIOJA generates
the rst signal, and gate UIOJB generates the xfr signal.
10.5 VOLT REGULATOR
1t140
* ....
":""""--1-<1
+10.5V
+
10.
~v
REGULATOR
A regulated 10.5 volts is required
by many of the
circuits in the tr-
ansceiver.
lt is
provided by the circuit comprised of Ql16, Ql17 and UI02.
The raw +14 volts is applied to
the emitter of
PNP
series trans-
istor Q116.
The output of Ql16, its
+14,VO-....
....04'"=----lII~-----..,f.....
collector, is sampled
by
the R-
140-R141-R142
voltage
divider,
with Rl41 serving as the "+10.5
set" control,
and its
wiper is
connected tothe
inverting in-
put
of UI02.
A reference de-
rived from
zener diode
CRll?
through
dropping resistor RIJJ
is applied
to
the
operational
amplifier's non-inverting input.
The output
of this stage,
a
IX:
voltage,
is applied to Qll? and
determines the degree to which it is allowed to conduct, and thence its col-
lector voltage.
lts collector,
in turn,
drives the base of Ql16 in such a
manner as to
control its degree
of conduction,
and thence to maintain its
output voltage at the required level.
WATI'MErERjSWR DEI'ECTOR
The wattmeter board circuitry
takes a sample of the current in the an-
tenna line via transformer TlOl,
and a sample of the voltage signal appear-
ing on the antenna line at the output of the transformer via the capacitive
voltage divider composed of CIOl, CI02 and trimmer CIOJ, the latter of which
allows precise alignment.
These signals are combined
in such a manner that
CRlOl produces a rectified output voltage proportional to
the magnetude
of
6-4
Advertisement
Chapters
Table of Contents
Troubleshooting
