Tektronix 2221 - Page 171

Appendix B - 2221 Operators
Can the
baud
rate
,
end
-
of - line
terminator
, or
parity
setups be changed from the RS - 232 - C controller ?
Q : Can I get readout information over the
communications interface ?
a
П
П
П
П
П
A : No.
Those
communications
parameters
must be set
up using the PARAMETERS switch on the
oscilloscope's side panel before the oscilloscope is
turned
on .
A : CRT
display
information may be
queried individually or
obtained as part of the waveform preamble . The
voits / div ,
sec / div ,
acquisition
mode
,
trigger
information , and cursor readouts are all available in
the 2221 and
2230.
Vertical
information
(
except for
Vertical Mode ) and cursor readouts are not available
with the
2220 .
Q :
Can
the GPIB
address of
the
oscilloscope
be
changed
from
the
bus or
the front -
panel ?
Q :
What
is the
26 - K
non -
volatile
memory
supplied with
the 2230 Communications option , and what are its
waveform
storage
capabilities ?
A :
The
GPIB
address and
other
communication
parameters are settable only from the PARAMETERS
switch on the
oscilloscope's
side
panel
, and
the
switch
settings are
read
only at
power on .
Q. Can a
waveform preamble be sent to the
instrument
?
A : Memory space for 26 , 1 - K waveforms , or 6 , 4 - K
waveforms , or any combination of waveform record
totaling not more than 26 K bytes is provided by the
added
memory
. The
non -
volatile
memory is
battery
backed for long -
term
waveform data
storage .
A : Yes
, a
waveform
preamble can be
sent to the
oscilloscope . That
preamble
should
correspond to the
curve data
that is sent
to the
target Save
Ref
memory .
Q : Can acquired waveforms be stored in the added
memory using
the 2230
front - panel
controls ?
П
Q :
Can
the
waveform
display
be
modified by
changing
the preamble fields ?
A : Yes . Waveforms may be transferred into and out of
the added memory using the Reference menu
selections
available
in the
Advanced Functions Menu .
Waveforms must be
transferred
through
one
of the
numbered Safe Ref
memory
locations
( REF1
- REF4 ) .
A : Modifying the preamble information so that it does not
correspond to the curve data invalidates the
waveform ,
but it
doesn't
usually
change the
way
it
is
displayed
. If
drastic changes are
made to the
preamble
(
such as data
encoding
or point
format ) , the
oscilloscope will
probably reject the curve
data as not
matching the preamble .
Q :
How are the
waveforms
stored
in the
added
memory
addressed via the
2230
communications
option
?
Q : What type of averaging is used for the AVERAGE
acquisition
mode
?
A : The added memory locations are designated REFA
through REFZ . These memory locations are accessed
through the REF1 - REF4 memory locations for both
reading and writing
using the
REFFrom and
SAVeref
commands ; they cannot be directly accessed .
A : A
normalized
averaging
algorithm is
used
.
As = A ( -1 ) + ( is - As - 1 ) ( Weight )
Q : What are the differences between Peak Detect ( PEAK )
and
Accumulated
Peak
Detect
(
ACCPEAK )
acquisition
modes ? Where
:
1
10
n
n
П
As
the
average after s
number
of
sweeps
,
Als
-
1
)
the
average after
( s - 1 )
sweeps
,
A : Peak Detect and Accumulated Peak Detect are both
envelope acquisition modes . Peak Detect captures
the
latest
maximum
and
minimum
points
during
a
single acquisition and discards them for the next
acquisition . Accumulated Peak Detect holds those
peak values
until reset so that
the changes over
time
are detectable . Accumulated Peak Detect is valid only
for triggered acquisitions and is not allowed in
untriggered modes . Peak Detect is valid for both
triggered and untriggered modes , since no peak are
held
between
acquisitions .
is
the
sth
input
sample ,
Weight
the
selectable
weighting
factor from
1/1
though
1/256
in
a
power of
2
sequence .
B - 19