LeCroy 9450 - Page 32

Leveling
Calibration:
This
part
of the
calibration
levels
all
ADCs
to
reference
ADC
No.
3
(which
is
a..
ways
80). For
this
it
adjusts
the
offsets
and
gains
associated
to each
S/H
and
ADC*
respectively.
The
procedure
may
encounter
the
following
problems:
l
=
S
a
^ a
convergence:
ADC
gain
correction
not
possible
for
one
or
more
ADCs.
2=of
fset
: Offset
cannot
be
adjusted
for
one
or
more
ADCs.
Phase
Calibration:
This
part
aligns
the
4
S/Hs
in
time
to
better
than
20
psec
by
an
iterative
procedure.
There
is
no
need
to
go
into
more
detail.
The
error
code
should
be zero.
However,
for
the
moment
Is
may
appear
on
some
units.
It
is
acceptable
for
the
time
being,
as
correct
operation
is
not
impaired
by this.
TDC
Calibration:
The
Interpolating
TDC
is
calibrated
at
40,
100
and
200
Hs/sec.
If
it
is
OK,
error
code
is
equal
to
zero.
Examples
:
Leveling
Cal.
Code
2300:
Offset
problem
at
400
and
200
Ms
Gain
conv.
problem
at
200
Ms
That's
all
that
is
required
for
a
quick
but
complete
internal
check
of
the
scope.
If
there
remain
error
codes
(not
equal
to
zero)
the
following
menus
may
be
used
to
get
more
detailed
information
on
possible
problems
and
failures.
7.2
Chan
1+2
Full
Test
The
DC
non-linearity
is
analyzed
automatically
for
BWL
ON/OFF,
50/ IMS
coupling
and
both
channels
for
the
sampling
rate
you
have
set.
The
last
two
lines
at the
bottom
of
the
table
list
the
largest
non-linearities
found
for
5
mV/di
v and
all
other
gains.
The
test
should
be
done
for
the
4
possible
sampling
rates
40,
100,
200
and
400
Ms/sec,
i.e.
for
time
bases
100,
50,
20
and
10 ysec/div.
However,
the
current
sampling
rate
is
not
displayed.
In
order
to
change
the
rate,
one
has
to
leave
the
menu
and
set the
time/div
appropriate
to
the
required
sampling
rate,
see
table
in
7.1.
The
non-linearities
should
not
be
larger
than
3
%
for
5
mV/div,
and
2
%
for
>
5
mV/div,
see
Figure
2.
7