HP 54501A - Digitize Command

Digitize
Command
The ACQUIRE and WAVEFORM
subsystems
are
subsystems
that
affect
the
DIGITIZE
command.
The
DIGITIZE
command
is
used to
capture
a
waveform
in
a
known
format
which
is
specified
by
the
ACQUIRE
subsystem.
When
the
DIGITIZE
command
is
sent to
an
instrument,
the
specified
channel
signal
is digitized
with
the
current
ACQUIRE
parameters.
To
obtain
waveform data,
you must
specify
the
WAVEFORM
parameters
for
the
waveform
data
prior
to
sending
the
:WAVEFORM:DATA?
query.
The
number
of
data
points
comprising a
waveform
varies
according
to
the
number
requested
in
the
ACQUIRE
subsystem. The
ACQUIRE
subsystem
determines
the
number
of
data
points,
type
of
acquistion,
and
number
of
averages
used
by
the
DIGITIZE
command.
This
allows
you
to
specify
exactly
what
the
digitized
information
will
contain.
A
typical
setup
is:
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;'
OUTPUT
707;
":ACQUIRE:TYPE AVERAGE"
<
terminator
>
":ACQUIRE:COMPLETE
100" <
terminator
>
":WAVEFORM:SOURCE
CHANNELl'
<
terminator
>
":WAVEFORM:FORMAT
ASCII"
<
tenninator>
":ACQUIRE:COUNT
4"
<
terminator
>
":ACQUIRE:POINTS
500"
<
terminator
>
":DIGmZE
CHANNELl"
<
terminator>
":WAVEFORM:DATA?"
<
terminator
>
This
setup
places
the
instrument
into
the
average
mode
with four
averages
and defines
the data
record
to
be
500
points.
This
means
that
when
the
DIGITIZE
command
is
received,
the
waveform
will
not
be
stored
into
memory
until
500 points
have
been
averaged
at least
four
times.
After
receiving
the
:WAVEFORM:DATA?
query,
the
instrument
will
start
passing
the
waveform
information when
addressed to
talk.
Digitized
waveforms
are
passed
from
the
instrument to
the
controller
by
sending
a
numerical
representation
of each
digitized
point.
The
format
of
the
numerical
representation
is
controlled
with
the
:WAVEFORM:FORMAT
command
and
may
be selected
as ASCII,
WORD,
BYTE,
or
COMPRESSED.
Introduction
to
Programming
an
Oscilloscope
HP
54501A
1-20
Programming