Chapter 7 SCPI
The Measurement subsystems
WCDMA Options Version 6.20
239
:MEASure[:CONTinuous] MEASure commands that are stated with or without the optional :CONTinuous
command element will make the 4400 perform the related measurement for an
unlimited number of times.
The measurement will only be terminated if a new MEASure command of the
same or related type is issued (see Notes above).
Syntax
:MEASure[:CONTinuous]<{:measProp}>[?]
Parameters
The one-shot measurements do not require any parameters.
Description
Starts the (continuous) measurement of the specified measurable property.
The CONTinuous command element is optional.
Unless a measurement result is read out (using the FETCh subsystem), no measure-
ment result values will be given back.
The measurement result(s) of any measurement will be stored internally. Any previ-
ously stored result will be overwritten as soon as a new measurement result has been
achieved.
The latest result measured may be read out using the FETCh subsystem.
Any FETCh command will wait for a measurement result value(s) to be available. In
case there is more than one measurement result value, the single measurement result
values are separated by commas (like e.g. “50.5,3.46”). Should the FETCh command
fail to obtain a measurement result value (because e.g. the current state of the 4400
does not allow the measurement to be performed or completed), a timeout will occur
and an error message will be added to the 4400’s internal error queue.
The related flag in the STATus subsystem will be set, too.
In case this is the first error message to appear within the error queue, the error indi-
cator bit of the service register (bit 2) will be set as well.
The main application of the combination of the MEAS and the FETC subsystems:
Starting a measurement that takes some time to deliver a measurement result back
(e.g. the BER measurement. After the measurement has been started with the MEAS
command, the test set ‘is free’ to perform other tasks. If in this case the query form of
the MEAS command is used, the test set is blocked until a measurement result is
available.
Sometimes, measurement results will need to ‘sweep in’. In this case, the first mea-
surement result might be totally misguiding. Using the MEAS command will allow
the measurement result value to stabilize on a meaningful result before the latest
result value is read out using the FETC subsystem.
Query
The query form of any MEASure command will start the (continuous) measurement of
the specified measurable property.
The CONTinuous command element is optional.
After the first measurement has been completed, the measurement result value(s)
will be delivered back in a string as outlined above.
Should the query fail to obtain a measurement result value, a timeout will occur and
an error message will be added to the 4400’s internal error queue as explained above.
The main application of the query form of a MEAS command is speed. When com-
bined with ‘fast’ measurements (like e.g. the fast power level measurement), the
query form of a MEAS command delivers measurement results as fast as possible.
Note: The measurement started with the query form of the MEAS command will be
continued in the background. Any further measurement result values may be read
out, using the appropriate FETCh command.
To Next Page
Loading...
