Fluke PM-3370B Sander User Manual


 
4 - 84 COMMAND REFERENCE
Limitations:
The MTB value of 2 ns is only possible for the PM339xB CombiScope
instruments.
If SENSe:SWEep:REALtime is ON, the MTB range is from 200 seconds to
250 nanoseconds, and sequential sampling is not guaranteed.
In a similar way, the time value Ts that is associated with a trace sample point can
be calculated from the following expression:
Ts = <sample_index>
*
SENSe:SWEep:TIME / (TRACE:POINts - 1)
where <sample_index> is the point number of the sample in the trace.
After a
*
RST command, the sweep time is 10 milliseconds.
Coupled values:
There exists a coupling between programming of the sweep time and the number
of trace points (acquisition length). The coupling is one way, which means that the
sweep time changes if the acquisition length changes. Example:
- Send
*
RST
The number of trace points is 512.
- Send
SENSe:SWEep:TIME .04
The sweep time is specified at 40 ms. The MTB becomes (0.04
*
50) / (511),
which is rounded to 4 ms. The result of this is that the sweep time is changed
to (0.004
*
511) / 50 = 0.04088 seconds.
- Send
TRACe:POINts CH1,4096
The number of trace points becomes 4096 instead of 512. The result of this is
that the sweep time becomes 8 times as high.
Note: When the magnifying factor is
*
1, always 500 sample points (10 x 50) of
the total acquisition length are visible on the display. So, if the acquisition
length is 4096 samples, only 1/8 of the trace is displayed on the screen.
Example:
Send
SENSe:SWEep:TIME? Requests sweep time
Read
<sweep_time> Reads sweep time
Send
TRACe:POINts? CH1 Requests nr of trace points
Read
<acq_length> Reads number of trace points
MTB = 50 * <sweep_time> / (<acq_length> - 1) Calculates the MTB
PRINT "Main Time Base ="; MTB; "s/div" Prints the MTB
Front panel compliance:
The SENSe:SWEep:TIME command is the remote equivalent of the front panel
TB MODE "s VAR ns" keys.