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34
released
will start
the time-base generator.
The
tir^e-base
generator
is
then blocked
until
the
SINGLE
button
is
pressed
again.
The
NOT
TRIG'D
lamp
will light
up
as
soon
as
the
SINGLE
button
is
depressed
and
remains
lighting until
the
trigger
pulse
arrives.
Fig.
2.4.
Scanning
the
waveform
by means
of
the
LEVEL
potentiometer
2.2.5.
Time-base
magnifier
(R2/S3)
The
time-base magnifier
is
operated
by
a
push-pull
switch incorporated
in
the
horizontal-POSITION
control
If
this
switch
is
pulled to position
xIO, the
sweep
speed
of the
main
time-base generator
is
increased
by
a
factor
of
10.
Thus, the portion
of
the
signal
displayed over
a
width
equal to
one
division
in
the centre of the
screen
in
the x1 position
(TB
MAGNifier
depressed),
will
occupy
the
full
width
of the screen
in
the
xIO
position.
Any
portion of the
trace
can be brought
on
to
the screen
by
the
horizontal-POSITION
control for
scrutinisation.
In
the
xIO
position,
the
time
coeffcient
is
determined
by
dividing the indicated
TIME/DIV
value
by
10.
2.2.6.
Use
of
the delayed time-base
The
delayed time-base can be used
for
the accurate
study
of
complex
signals.
When
push-button
MAIN TB
of
the delayed
t.b.
trigger-source controls (S21
)
is
operated,
immediately
the delayed time-base
is
on
(i.e.
the
TIME/DIV
switch
is
not
at
OFF),
a
portion of the displayed
signal
is
intensified
in
the
MAIN TB
position of
the horizontal
deflection controls
(S2).
The
DELAY
TIME
control (R1
)
enables
this
intensified
portion to be
shifted
along the
time
axis.
The
duration of the
intensified
portion,
its
length,
can be
controlled
in
steps
and
continuously
by means
of the
TIME/DIV
controls of the
delayed time-base
generator.
When
push-button
DEL'D
TB
of the horizontal deflection controls
(S2)
is
operated, the
intensified
portion occupies the
full
width
of the
screen.
In
the
DEL'D TB
position,
the delay time,
{i.e.
the
interval
between
the
starting
point of the
main
time-base
and
the
starting
point of the
delayed
time-base)
is
determined by
the
settings
of the
main
TIME/DIV
controls
and
the
DELAY
TIME
control.
If
one
of the other
del'd
t.b.
trigger-source controls (S21
)
is
operated, the delayed time-base
is
started
by
the
first
trigger
pulse that
occurs
after
the
selected
delay time.
This
trigger
pulse
is
supplied
by
the
trigger
unit
of
the delayed time-base generator. This position
is
used
when
time
jitter
would
otherwise
give
a
blurred
image
of the
detail
under
observation. This
time
jitter
could be
part
of the
signal
being
investigated
or, at
extreme
magnification,
originate
in
the time-base
circuits.
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