Rohde & Schwarz CMU-K20, Operating Manual

Page: 175 / 646

CMU-K20/K21/K22/K23/K24
Signalling: Power Measurements
1115.6088.12 4.97 E-12
Power Measurements
The menu group
Power
is designed to measure the RF output power of the MS transmitter. The power
of a normal burst in a single timeslot or in up to 4 consecutive timeslots, the power of an access burst,
the averaged power and its evolution over several slots or frames can be analyzed. In addition, the
average power can be measured as a function of the power control level (PCL) of the mobile. The
different measurements are treated as different applications; the results are displayed in separate
Power
measurement menus
.
The popup menu
Power Configuration
is used to configure the
measurements.
Most applications and settings of the
Power
menu do not depend on the signalling state and
correspond to those of the menu
Power
in the test mode
GSM400/850/900/1800/1900-MS Non
Signalling
. For a detailed description of these applications refer to p.
4.9
ff. The following two
applications are related to signalling issues and therefore not available in
Non Signalling
mode:
•
Application
P/PCL
•
Application
P/t Access GMSK
P/PCL
In
Signalling
mode, the average burst
Power
can be measured as a function of the PCL of
the connected mobile phone. This parameter is not available under the conditions of a
module test. Therefore, application
P/PCL
is not included in the
Non Signalling
measurements.
The
P/PCL
measurement represents a fast method of measuring the average burst power
transmitted on all PCLs supported by a mobile. The measurement relies on the fact that a
GSM mobile, when changing from one PCL to another, steps through the whole range of
intermediate PCLs, dwelling on each level for a period corresponding to 13 TDMA frames
(577
µ
s x 8 x 13
≈
60 ms). The CMU measures the average burst power in the whole PCL
range, starting with the highest output power level (i.e. the smallest PCL, see
Table 4-8
on
page
4.112
).
The P/PCL measurement is combined with frequency hopping on seven uplink
GSM channels. In addition, a limit check with PCL-dependent tolerances is
performed. The results are output in tabular form.
P/t Access GMSK
The
P/t Access GMSK
application measures the power of an access burst over one burst
period. The measurement curve obtained can be further processed to determine an average,
minimum, or maximum result and calculate the average over the whole burst. Access bursts
are used by the mobile station for initial random access to the network and for handover, so
they can be measured in
Signalling
mode only. As there is no mode where the mobile
transmits access bursts in consecutive TDMA frames, only single shot measurements can be
made. Besides, the
P/t Access GMSK
application is analogous to
P/t Normal GMSK.
The properties and use of access bursts in GSM networks are described in section
Limit lines
(Power Configuration – Limit Lines)
on page
4.32
ff.
Note:
Power
measurements on normal bursts are performed at the MS output power set via
PCL
(see PCL softkey on p.
4.155
) or the corresponding parameters for multislot or packet data
mode. In contrast, the access burst is transmitted before a call is set up. The
P/t Access
Burst
measurement is performed at the maximum power for the cell
PMAX
(see PMAX
parameter on p.
4.161 )
.
Measurement Menu (Power)
The graphical measurement menu
Power
displays the results of the power measurement.
•
The measurement control softkey
P/t Normal GMSK
(which changes to
P/Frame, P/PCL etc.,
depending on the power measurement application selected) controls the
Power
measurement,
indicates its status
(RUN | HLT | OFF),
and opens the configuration menu
Power Configuration
. The
hotkeys associated to the measurement control softkey define the scope of the
Power
measurement.
深圳德标仪器
135-1095-0799