Filter
Top Products
interpolators by using the
CAL:INT:AUTO ONCE command.
Block Measurements
When dumping measurement results into
the internal memory, it is important to
program the arming and triggering coun
-
ters in the best way. For maximum mea
-
surement rate use the block armed mode.
To do this set:
:ARM:STARt:LAYer:COUNt81
and
TRIG:COUNt8 <N>
where <N> is the number of measure
-
ments in a block.
Real Time Calculation
Normally the counter calculates the re-
sults in “real time.” This means that for
each measurement, the counter immedi-
ately calculates the result based on the
raw data information in various counting
registers. It needs to do this in order to
display the result, make mathematical
calculations, limit testing and statistical
calculations. It is possible to defer the
calculations until the controller requests
these values. The counter intermediately
stores the measurement data in a packed
format. This is done with the command:
:SENSe:INTernal:FORMat8 PACKed.
+
This is the most important com
-
mand when you want to improve
the measurement rate for block
synchronized measurements.
Note: If you want a very high speed
you must set :AVER:STATE8OFF and
:ACQ:APER8 MIN.
40000 measure-
ments/second
(Only PM6681)
PM6681 can make measure every period
of a signal with up to 40 000 Hz. This is
called “Back-to-Back” period measure
-
ments and in only available via GPIB.
The high speed is obtained when the
PM6681 measures low-resolution mea
-
surements directly to its internal memory.
That memory can store 6143 measure
-
ment results. When full, the measurement
must be stopped, and the results fetched
by the controller. )
Note also that some functions are dis-
abled to obtain high measurement speed:
You cannot use external arm/trig or
hold-off. Statistics is also disabled.
Example: 1000 back-to-back periods
:SENS:FUNC8"PER81"
Select period as measurement function
:INP:COUP8DC Select DC coupling
:INP:LEV:AUTO8OFF Turnoff AutoTrigger
:INP:LEV81 Set fixed trigger level
:SENS:ACQ:RES8LOW Select low resolu
-
tion/high speed measurements
:SENS:INT:FORM8PACK Suspends the re
-
sult calculation until the capture is
ready
:TRIG:COUN81000;:ARM:COUN81 Set up
PM6681 for 1000 measurements
:INIT Start a capture
:FETC:ARR?81000 Fetch the 1000 results
from the internal PM6681 memory
How to Measure Fast
40000 measure- ments/second 7-9