Tektronix 2246 - Page 52

Measurement
Processes
and
Applications—
2246
Operators
measurement
accuracy
on
the
CH
3
or
CH
4
Input
signals
will
be
less
accurate
than
available
on
the
CH
1
or
CH
2
input
signals.
Volts
cursors
are
also
available
for
making
measurements
in
the
both
the
A
Horizontal
MODE
and
the
X-Y
Horizontal
MODE.
,
Voltage
Measurements
Using
Cursors
VOLTAGE
DIFFERENCE.
Use
the
following
procedure
steps
as
a
guideline
in
making
voltage
difference
measure-
ments
using
the
positionable
cursors.
t.
Set
up
the
signal
to
be
measured
and
the
front
panel
controls
as
indicated
in
steps
1
and
2
of
the
+PEAK
VOLTAGE
MEASUREMENT
procedure.
2.
Press
the
CURSORS
button
to
display
the
measure-
ment,
selection
menu
and
select
the
l-
VOLTS
I
cursors.
The
Voltage
cursors
are
initialized
to
the
peak-to-peak
lev-
els
of
the
lowest
numbered
displayed
channel
of
either
CH
1
or
CH
2
(see
Figure
6-9).
NOTE
Voltage
cursors
are
initialized
to
levels
seen
by
the
peak
detector
circuitry.
Noise
and
other
signals
rid-
ing
on
the
signal
to
be
measured
will
cause
a
slight
displacement
of
the
cursors
from
the
displayed
waveform
peaks,
and
above
50
MHz,
the
bandwidth
rolloff
of
the
trigger
circuit
will
affect
the
initial
cursor
positions
on
the
waveform.
3.
For
a
peak-to-peak
voltage
measurement,
slightly
reposition
the
cursors
as
necessary
to
precisely
align
them
with
the
peak
amplitudes
of
the
waveform,
and
the
work
is
done.
The
l-
OR
DELAY
control
positions
both
cursors
together
{keeping
the
original
spacing),
and
the
-1
OR
A
control
positions
the
independent
cursor.
Then,
simply
read
the
measurement
value
displayed
in
the
top
line
of
the
readout.
4. To make voltage difference measurements between
any other locations on the waveform, simply move the l-
cursor
to
the
new
point
of
interest,
then
position
the
independent -I cursor to second point on the waveform
and read the voltage difference.
DC
VOLTAGE.
Plus
and
minus
dc
voltage
measure-
ments
using
ground
as
a
reference
are
made
using
the
rh
VOLTS
-i
cursors.
The
ground
tracking
cursor
is
fixed
at
the
de
ground
level
of
the
applied
signal
and
the
6-12
PK-PK VOLTAGE
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Figure
6-9.
Voltage
difference
measurement
using
cursors.
independent
cursor
above
or
below
ground
as
necessary
to
measure
the
instantaneous
dc
voltage
at
the.
cursor
position.
Use
the
following
procedure
steps
to
set
up
to
measure
ground-referenced
dc
voltages.
1.
Set
up
the
signal
to
be
measured
and
the
front
panel
controls
as
indicated
in
steps
1
and
2
of
the
+PEAK
VOLTAGE
MEASUREMENT
procedure.
NOTE
An
important
point
to
remember
here
is
to
have
the
Input
COUPLING
set
to
DC.
A
question
mark
will
appear
in
front
of
the
measurement
value
readout
if
the
coupling
is
not
DC
because
any
dc
offset
present
with
the
applied
waveform
will
be
removed
when
AC
Input
COUPLING
is
used.
2.
Press
the
CURSORS
button
to
display
the
measure-
ment
selection
menu
and
select
the
rh
VOLTS
-l
cursors.
The
independent
cursor
is
initialized
to
the
+PEAK.of
the
input
waveform.
3.
Position
the
independent
cursor
using
the
-i
or
A
control
to
the
measurement
point
on
the
waveform
and
read
out
the
dc
value
of
the
cursor
position
(shown
in
Figure
6-10).
(The
l-
or
DELAY
control
has
no
effect.)
REV APR 1987