HP 54501A - Page 207

All
voltage
values
are
returned
in
volts.
Returned
voltage
values
are
measured
with
zero
volts
as
the
reference.
The
value
returned
for
the
VDELTA?
query
is
the difference
between
VMarker
1
and
VMarker
2
in
volts.
All
time values
are
returned
in
seconds. Returned
time
values
are
measured
with
the
trigger
point (time
0)
as
the
reference.
The
value
returned
for
TDELTA?
is
the
time
difference
between
the
stop
and start
markers.
Measurements are
made
on
the
displayed wavefonn(s) specified
by
the
SOURCE
command.
The SOURCE
command
allows
two
sources
to
be
specified.
When
two sources
are
specified,
VMarker
1
is
assigned
to
the
first
specified
source
and
VMarker
2
is
assigned
to
the
second
specified
source.
VDELTA
is
the
only
measurement
that
uses
two
sources.
Most
measurements can
only
be
made on
a
single
source.
If
one
of these
measurements
is
made
with
two sources
specified,
the
measurement
is
made
on
the first
source
specified.
More
information
about
measurement
algorithms
can
be
found
in
Appendix
A.
If
the
horizontal
scaling
is
questionable,
an
"error
11"
is
placed
in the
error
queue.
In
this
case
the
value returned
is
the
most accurate
that
can
be
made
using
the
current
scaling.
You
might
be able
to
obtain
a
more
accurate measurement
by
rescaling
the
horizontal
to
obtain
more
data
points
on
the
edge.
Refer
to
figure
14-1
for
the
syntax diagram
of
the
Measure
subsystem
commands.
HP
54501A
Programming
Measure
Subsystem
14-3