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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