Rohde & Schwarz CMU-K20, Operating Manual

Page: 240 / 646

Signalling: Connection Control
CMU-K20/K21/K22/K23/K24
1115.6088.12 4.162 E-12
The present chapter describes the parameters related to circuit switched operation of the mobile
phone. Tests in
Packet Data (GPRS)
mode require option CMU-K42. They are described in section
RF
Signals of the CMU (Connection Control – BS Signal)
on p. 4.195 ff.
The CMU provides a softkey-oriented version of the
BS Signal
tab and a table-oriented version with
extended functionality. The
BS Signal
hotkey toggles between the two versions if it is pressed
repeatedly.
Softkey-oriented Version: Single Slot Mode
The
Slot Mode
of the mobile can be set by means of the
Slot Mode
softkey before a call is established.
While
Single Slot
mode is selected, the
Level Mode
softkey is inactive. The softkey-oriented version of
the
BS Signal
tab determines
•
A
Frequency Offset
by which the RF frequency of the BS traffic and control channel (BCCH) signal
is modified
•
The transmission
Mode
,
BCCH Level
and GSM channel number
(RF Channel)
of the CMU's
Broadcast Control Channel (BCCH)
•
The level
(TCH Level)
, GSM channel number
(RF Channel)
,
Hopping
sequence and
Timeslot
of the
CMU's traffic channel (TCH)
Fig. 4-73 Connection Control – BS Signal (panel, single slot)
The left half of the BS Signal tab contains the following BCCH settings:
Frequency
Offset
The
Frequency Offset
softkey determines the frequency offset of the CMU signals
from the value defined under
RF Channel
. This enables fine tuning of the signal
generated by the CMU, for example for simulating a Doppler shift (due to a relative
movement between mobile and CMU) or de-tuning of the base station or the MS
receiver. The value range of the frequency offset is – 100 kHz to +100 kHz
(covering the entire GSM channel width) such that the CMU is able to transmit on
any frequency within the selected GMS band.
For special applications it is possible to multiply the frequency offset with a random
sign; see
Enabling the Random Frequency Offset
on p. 4.167 .
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