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H S2005-301D
4.
The
controls and
connectors on the rear panel of the monitored attenuator
are
as
follows
:-
(1)
HT inlet.
For
cormecting one of
the
attenua
tors by means of h.t. lead
TM
705:3.
(2
)
INPUT
sockets.
For
connecting
the oscillators by means
of
coaxial leads
TM
(j95R.
PREPARATION FOR USE
Power
supply
5.
The
instrument
can
be operated from
an
a.c.
supply
or a d.c. source, according to the
setting of
the BATTERY
/
MAINS
switches
at the rear
of the
oscillators
.
6.
The
instrument
is
adjusted
for
an a
.
c. supply
of 95
V
to
130
V
or
190 V
to
260
V
(Chap.
5
).
After
checking
that
the
mains
voltage
adjustment
is
correct,
connect
to the
mains
by means
of
lead
TM
7052
.
When
fitting a supply
plug ensure that the
conductors
are connected
as
follow
s:-
Earth- green/yellow, Neutral- blue
.
Live -brown
.
7.
A
d.c.
source can
be
between 65 V and
90 V.
It
must
be
floating.
Dry batteries
can
be
used, but it
should
be noted
that
the drain
is
about 60 rnA.
Connect leads from
the
source to the
appropriate
terminals marked
+
and
- at the r ear of the oscillators.
Interconnections
8.
DC
is
required
by
the monitored
attenuator.
This is fed from
one
of the oscillators by
means of lead
TM
7053.
9.
It
is
usually most
convenient
to use
the
instrument with the OUTPUT sockets on the rear
panels
of the oscillators
linked to the INPUT sockets
on the
rear panel of the monitored
atte nua
-
t
or by
means
of
leads
TM 6958.
Switching
on
10.
Switch
on
one
oscillator a
nd the monitored
attenuator
by turning the appropriate SUPPLY
switch clockwise.
Switch
on
the other oscillator,
if
required, by turning its
SUPPLY
switch
clockwise.
The instrument is
ready
for
use
almost
immediately; the time taken to reach
a
high
degree
of
stability depends on
the
frequency
range,
but
is normally less than
!
min.
11.
If
a
load
is
already
connected,
and
is
sensitive, it
may be advisable to turn the SET OUT-
PUT
controls
counter-clockwise before switching
on.
Initially, the generated
signal may rise
to
approximately
50%
above
normal
amplitude before stabilization takes place.
Also
-when
the load impedance
is high and
the
SET OUTPUT
control
is fully
clockwise-
a
d.c.
pulse of
several volts
appears
briefly
when the
instrument
is
switched
on and
switched
off, the pulse
being
positive
and negative
respectively
.
SETTING
FREQUENCY
12.
Set an oscillator
to
a
particular frequency as follows
:-
(1)
Set
the FREQUENCY
RANGE switch
to the
range
which
includes
the required fre
-
quency.
On
the
front panel, each position
of the switch
falls
between
two figures, which
indicate in
Hz
the frequency limits of the range
obtained
in
that
position.
Ea ch
position
is
also
marked
with
a
letter, A orB,
indicating
whether
scale A orB
must
be read
on
the
frequency
dial.
(2)
Turn
the
FREQUENCY control so that
the dial
indicates
the required frequency,
reading
scale
A
or
B according t
o
the setting
of the FREQUENCY
RANGE switch.
Readings on
the scales are
eithe
r direct
reading
or
require
to
be
multiplied by
10
or
100
according to
the
range selected.
Chap
.
3
Page
-!
Nov. 79
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