Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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CMU-K20/-K21/-K22/-K23/-K24 Signalling Mode
1115.6088.12 2.19 E-10
Additional Information... Alternative Settings
and Measurements
... on Step 5
"
Power control level (PCL)
Dynamic power control is used in GSM networks to reduce
the output power of the mobile station as far as possible. In
practice the base station sets the mobile power on a dimen-
sionless scale of
power control levels (PCL) ranging from 0 to
31. In GSM900, PCL 0 corresponds to the largest nominal
output power (39 dBm), power control levels between 16 and
31 can be set for phase II mobiles only.
In contrast to the PCL the power class characterizes the
nominal maximum output power of the mobile. Depending on
the power class of the mobile the range of possible PCL set-
tings may be restricted.
'
chapter 4, p. 4.112 ff.
PCL levels and power classes are
listed in section
Limits for the
Average Burst Power in chap-
ter 4.
#
Traffic channel
The channel number of the BS traffic channel signal is de-
fined according to GSM specifications as explained for the
Non Signalling mode (downlink, see Analyzer/Generator
menu on page 2.7 ).
The traffic channel can be fixed or changed periodically (fre-
quency hopping). Frequency hopping is defined by means of
one of the four hopping sequences A, B, C, D.
With the CMU basic unit timeslots 2 to 6 may be selected for
the traffic channel because the timeslots 0, 1, and 7 are oc-
cupied by the BCCH and for reconfiguring.
'
chapter 4, p. 4.161 ff.
Besides the four GSM standard
hopping sequences A to D arbi-
trary sequences consisting of up
to 64 channel numbers may be
defined and used.
Out-of-tolerance power measurements
If a power measurement is out of tolerance, please ensure that the attenuation of any cables and/or
antenna couplers used is being taken into account by the CMU. As some GSM power levels must
be within
±
2 dB of the nominal value given in the specifications, even a small attenuation can result
in an out-of-tolerance measurement.
External attenuation values for each input/output may be entered in the RF tab of the Connect.
Control menu
The cables, RF connections and antenna couplers must also be in good condition for satisfactory
measurements. Dirty or broken RF connections can cause problems at the high frequencies used by
GSM networks.
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