Rohde & Schwarz CMU-K20, Руководство по эксплуатации

Страница: 43 / 646

CMU-K20/-K21/-K22/-K23/-K24 Non Signalling Mode
1115.6088.12 2.9 E-10
Additional Information... Alternative Settings
and Measurements
... on Step 2
"
Power Configuration menu
The Power Configuration menu contains three tabs defining
•
Measurement control and statistical settings (Control),
•
The tolerance template for the burst (Limit Lines),
•
PCL-dependent limits for the average burst p ower (Lim-
its)
'
chapter 3.
Settings made in the Power Con-
figuration menu apply to power
measurements only.
Settings made in the Connect.
Control menus apply to the entire
function group and mode
GSM900-MS Non Signalling .
#
Repetition mode and Stop Condition
If no stop condition is imposed (Stop Condition = None), the
Repetition mode determines whether the measurement is
•
Continued until explicitly stopped by the operator (Con-
tinuous),
•
Stopped after one statistic count (Single Shot).
By default, a statistic count comprises 100 bursts. With Stop
Condition = On Limit Failure , the measurement is stopped af-
ter the first burst which is out of tolerance.
'
chapter 3.
The Statistic Count is defined in
the Control tab of the Power Con-
figuration menu.
The stop condition On Limit Fail-
ure should be selected if the limit
check represents the main pur-
pose of the measurement.
The limits can be modified in the
Limit Lines tab of the Power Con-
figuration menu.
$
Measurement in the HLT state
The average and peak power of the last burst measured is
indicated in the output fields
Average and Peak .
In contrast, the modulation measurement is still running. The
results for the frequency and phase errors are periodically
updated.
'
CMU manual
See the sections on measure-
ment control in chapter 3 and 5.
... on Step 3
%
Power menu
The diagram in the Power menu, application Power/t Norm.
GMSK shows a normal burst with a length of 148 bits (plus a
guard period of 8.25 bits). The time scale of the diagram
ranges from –10 bits to 156¾ bits covering the useful part,
the rising and falling edges of the burst. The ordinate ranges
from –80 dB to +10 dB, the 0-dB reference level is equal to
the carrier power.
Note that settings made previously ( Power Configuration
menu) are preserved in the whole measurement group. Ac-
cordingly, the status of the measurement is still
HLT. The dia-
gram is fixed showing the last burst measured.
'
chapter 4, p. 4.9 ff.
The GSM power template is de-
fined relative to the carrier power.
For low signal powers, a looser
absolute limit is to be applied at
the beginning and the end of the
power ramp (areas 1, 2, 7, and
8). This yields the distorted tem-
plate that we observe in the pre-
sent example.
深圳德标仪器
135-1095-0799