Rohde & Schwarz 1094.0006.50, Operating Manual

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CTS55 Getting Started With Manual Test
1094.0006.55 6.11 E-6
Explanations:
c
Phase/Frequency Error
GSM mobile phones synchronise themselves to the frequency of the base station. The CTS
therefore measures the frequency error (frequency offset) of the mobile transmitter and not the
absolute frequency. The phase error is measured by calculating the expected phase of the RF signal
from the decoded bits and comparing this to the actual phase measured by the CTS. Two values are
defined in GSM: the absolute maximum (peak) error in a burst and the average (RMS) error in a
burst.
d
Power Ramp
The power ramp is displayed with approximately 55 dB dynamic range.
Please note that it is possible for the average power during a burst to be out of tolerance whilst the
power ramp is in tolerance, and vice-versa. This is because the power ramp tolerances, according to
the GSM specifications, are mainly based on variations from the average power and are not absolute
values.