Appendix A
SCPI Command Reference
MEASure subsystem
560
4460 GSM System Option and 4468 EDGE System Option
Version 12.20
Description
Starts a continuous measurement of the mobile's UL burst shape. To read out the
measurement result values of the last burst sampled, use the
:FETCh:EGPRs:RFTX:BLOCkdata:BURStshape
command.
The aim of this measurement is to obtain the pure RF power levels, sampled by the
Willtek 4400 in order to display the shape of the burst graphically on another com-
puter or to perform some special analysis of the burst shape.
For details regarding the burst measurement, also refer to section Burst Test Menu.
Further information regarding this kind of measurement can be found in section
:MEASure:...:BLOCkdata
.
Query
The query form of this command will start the measurement and return an array of
measurement result values as soon as the first measurement has been completed. The
string delivered back will contain 711 floating point real numbers with the physical
dimension of dB (except the first two).
The first data position of the array is the absolute position of the middle of the burst
(i.e. bit 73) within the burst data supplied. In order to allocate the RF power level
obtained for the middle of the burst,
add 2
to this first value of the array to find the
relative position within this data array (as the first two positions of this array are no
data values).
The second number is the
absolute
peak power level of the burst in dBm, obtained at
the middle of the burst.
All following 709 data values are
relative
RF power levels (in dB) with the peak power
level (second data value of the array) being the reference.
The single measurement result values are separated by commas.
Example
:MEAS:EGPRs:CONT:BLOC:BURStshape?
The array returned in this example is: "
353.0,10.0,-73.5,-69.6,-70.8,
...-0.1,0.0,0.2,...-68.4
".
The data have the following meaning:
353.0
on the first position means that the
absolute position of the middle of the burst is position 353 of the burst data array.
Thus, it can be found on position 355 of the data block returned.
The relative power level at the middle of the burst will always be
0.0
as it is the ref-
erence point.
The peak power of the burst (obtained at the reference point 'middle of the burst')
can be found on the second position of the data array and is
10.0
dBm in this
example.
Then follows the relative RF power levels sampled at the various time positions of the
burst (
-73.5,-69.6,
... dB). This means that the absolute power level at the first
position sampled is -63,5 dBm (-73.5+10.0).
All the remaining data values are relative RF power levels sampled by the Willtek
4400 during the burst period.