Tektronix 2221 - Page 117

Options and
Accessories
--
2221 Operators
Table
7-30
(
cont )
Commands
Description
.
ALL
WFMpre NR.Pts : < NR1 >
П
Л
П
1 П
П
П
D
П
<
NR1 > is
the
number
of
points in
the
waveform .
Each
point
can
be
a
single Y
value
(
with time
implied
) ,
an X - Y
pair , or a
Max -
Min pair .
Although the
record
length
is
either
1024
data
point
or
4096
data points , the
NR.Pts <
NR1 >
value
may be
256 , 512
,
1024
,
2048
, or
4096
points
. The
value
depends
on
the
number
of
channels
,
the
acquisition
mode
, and
whether
smoothing is on or
off . A table
expressing the
conditions and the
record length to
NR.Pts
ratio
value
follows :
NR.Pts to
Record
Length
Ratio
Number of
Channels
Acquire
Mode
SMOOTH
1
1
1
1
Rec / 1
Rec / 1
Rec / 1
Rec / 1
Rec /
2
Rec
/
2
Rec / 2
Rec / 2
Rec
/
2
Rec / 2
Rec / 4
Rec / 4
N
N
N
N
N
N
SAMple
AVErage
PEAkdet
ACCpeak
SAMple
AVErage
PEAkdet
ACCpeak
PEAkdet
ACCpeak
PEAkdet
ACCpeak
NA
NA
ON
ON
NA
NA
ON
ON
OFF
OFF
OFF
OFF
1
1
For
example
,
if the
number of
channels is
two and the
acquisition
is
peak
detect
with
smoothing off ,
the
number of
points for a
waveform
in a 4
Kbyte
record
is
4096
divided
by 4 (
1024
points
) .
ALL
WFMpre PT.Off : < NR1 >
<
NR1 > is
the
trigger
position
relative to
the
first data
point in the
record
.
For a
1024
point record , <
NR1 > for
PT.Off
ranges
from
4 to
1024
in
increments of 4 .
The
normal
values for a
4096
point
record
range
from
4
t04096 .
NOTE
an
1
7
П
П
П
п
П
1
<
NA1 > will
be a
negative
value
if
the
trigger
occurred
before the
first data
point
in
the
record
window .
Since
any
1024
point
window of a
4096
point
record
may be
transferred , the
legal
values
of
<
NA1 > for
PT.Off are
-3096 to
+4096
. If
the
PT.Off
value
is
unknown , -
10000
in
the <
NR1
>
value
returned
.
7-41