Rohde & Schwarz CMU-K20, Operating Manual

Page: 86 / 646

Non Signalling: Power Measurements CMU-K20/K21/K22/K23/K24
1115.6088.12 4.8 E-11
Power Measurements
The menu group Power is designed to measure the RF output power of the MS transmitter. The power
can be analyzed as a function of time in a single timeslot or in up to 4 consecutive timeslots.
Furthermore, the CMU evaluates the average power and its evolution over several consecutive slots or
frames. 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.
The different types of Power measurements are treated as applications which can be selected with the
Application softkey.
P/t Normal
The P/t Normal ... (burst power versus time) application measures the output power of the
DUT 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.
P/t measurements are provided for normal bursts at GMSK or 8MSK
modulation.
In addition to the burst power measurement, a limit check with tolerances depending on the
RF output power of the DUT and the modulation scheme is performed; see section
Limit
lines (Power Configuration – Limit Lines)
on p.
4.32
ff.
P/t Multislot The P/t Multislot application measures the output power of the DUT over up to 653 symbol
periods, corresponding to 4 timeslots plus an appropriate display margin. This
measurement is particularly suited to GSM multislot solutions like GPRS or circuit-switched
HSCSD where several timeslots can be allocated to a single connection.
The multislot measurement curve can be further processed to determine an average,
minimum, or maximum result and calculate the average power over each burst measured.
P/t Multislot measurements are provided both in Non Signalling and in Signalling test mode
and for normal bursts at GMSK and 8PSK modulation. In addition to the burst power
measurement, a limit check with tolerances depending on the RF output power of the DUT
and the modulation scheme is performed; see section
Limit lines (Power Configuration
– Limit Lines)
on p.
4.32
ff.
P/Slot The P/Slot applications measure the average burst power in a series of consecutive
timeslots. The average is taken over a section of the useful part of the burst; it is not
correlated to the training sequence. The result is displayed either in a bar graph (all eight
timeslots of a single TDMA frame,
P/Slot Graph application) or in a table (up to 512
timeslots, corresponding to a total test time of approx. 0.3 s, P/Slot Table application).
P/Frame The P/Frame measurement represents a fast and convenient method of monitoring the
behavior of the average burst power in a particular timeslot over a whole range of
consecutive TDMA frames. The measurement extends over a range of up to 256 frames,
corresponding to test times of less than 1.2 s. The average is obtained like in the case of
P/Slot measurements.
The P/Slot and the P/Frame measurement complement the P/t measurement where a large
number of bursts can be measured but the output of the average burst power is restricted to
current, average, minimum or maximum values within a statistics cycle (see
Display Mode
setting below). P/Slot and P/Frame returns all values; the applications are suitable
whenever the behavior or the stability of the average burst power in particular timeslots are
to be monitored over an extended time range in R&D.
RF Level
In all applications, the CMU measures at arbitrary RF input levels provided that they are
within the allowed range of the RF input connectors.
Signalling mode Note: In Signalling mode, where the CMU is able to test a broad range of signalling
issues, two further measurement applications are available (see section
Power Measurements on page
4.97
ff):
The average burst power can be measured as a function of the PCL of the
mobile phone (application
P/PCL) .
Access bursts from the mobile station can be measured (see also section
Limit lines (Power Configuration – Limit Lines)
on page
4.32
ff.
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