Rohde & Schwarz CMU-K20, Operating Manual

Page: 170 / 646

Signalling: Setting up a Connection
CMU-K20/K21/K22/K23/K24
1115.6088.12 4.92 E-12
Main
Service
The
Main Service
softkey selects
Circuit Switched
or
Packet Data
(GPRS or
EGPRS) operation of the MS under test. This softkey is disabled (grayed) if the
Network Support
is set to GSM. See also section
GPRS Signalling
on p. 4.187 ff.
Remote control
[:SENSe:]NETWork:MSERvice
Network
Support
The
Network Support
softkey determines whether the CMU acts as a BTS that
supports GSM only or GSM and (E)GPRS.
GSM
Circuit switched GSM operation without GPRS support
GSM + (E)GPRS
Circuit switched GSM operation with (E)GPRS support: The
CMU reports to the MS that the CMU/current cell supports
(E)GPRS. The MS can react to this message and attempt a
GPRS attach provided that it also supports (E)GPRS.
The
Network Support
parameter is available only before the MS is synchronized
(i.e. in the GSM signalling states
Signal Off
or
Signal On).
The
GSM + (E)GPRS
setting is a pre-condition for all (E)GPRS-related signalling procedures and
measurements such as the
Main Service
selection.
If the
Packet Data
main service is selected, the
Network Support
must be either
GSM + GPRS
or
GSM + EGPRS
.
Remote control
CONFigure:NETWork:NSUPport GSM | GGPR | GEGP
Wideband
Power
The
Wideband Power
softkey controls the wideband power measurement and
indicates its status
(RUN | HLT | OFF)
. The status can be changed after softkey
selection (pressing once) by means of the
ON/OFF
key or the
CONT/HALT
key.
The measurement result is in units of dBm. The analog bar to the right of the
softkey shows the measured power relative to the expected level from the MS, i.e.
the nominal output power corresponding to its power class and PCL. The display
range is between
Nominal Power – 10 dB
and
Nominal Power + 10 dB
.
The wideband power measurement is performed at the Front End of the CMU and
yields the peak power of the input signal inside a wide frequency range. For GMSK
modulated GSM signals, the result of the wideband power measurement is usually
slightly higher than the result of the
Power
measurement which is obtained with
different filter characteristics. The main purpose of the wideband power
measurement is to indicate whether an input signal is available and whether it is in
the expected range.
Note: An additional quick and precise power measurement is available in
remote control (keyword
NPOWer
).
Remote control
INITiate:WPOWer
FETCh:WPOWer:STATus?
READ[:SCALar]:WPOWer?
FETCh[:SCALar]:WPOWer?
SAMPle[:SCALar]:WPOWer?
Connection Control with Signal (State Signal On)
In addition to the parameter overview described in section
Connection Control with Call Established
on
p. 4.148 ff, the
Network Support
and
Main Service
softkeys, and the wideband power measurement
described in section
Signalling Control without Signal (State Signal Off)
on p. 4.90 ff., the
Connection
(Signal On)
tab contains the following softkeys which lead to other services or signalling states:
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