General Description
R&S
®
CMW-KM750/-KM751
11
User Manual 1173.9670.02 ─ 05
Fig. 3-1: Connecting an RF transmitter to the instrument
3.1.2 Measuring an Uplink TD-SCDMA Signal
After connecting your TD-SCDMA UE to the R&S
CMW you have to adjust the following
analyzer settings to the properties of the analyzed UL TD-SCDMA signal:
●
The analyzer "Frequency"
●
The "Expected Nominal Power" and (optional) a "User Margin" and "External Attenu-
ation". Recommended values: "Expected Nominal Power" = peak power of the UE
signal over the entire measurement range; "User Margin" = 0 dB (the smallest pos-
sible value ensures maximum dynamic range).
For synchronization to the received signal and proper decoding, the "UE Signal Info"
settings in the configuration dialog must be in accordance with the measured signal. In
particular, ensure that the following parameters match up:
●
The "First Active Uplink Slot Number"
●
The position of the duplex "Switching Point"
●
The "Scrambling Code" and the "User Number"
●
The "Modulation Type"
The R&S
CMW can auto-detect the spreading factors and channelization codes of the
channels.
With matching "UE Signal Info" settings, the R&S
CMW is able to decode the signal and
determine its slot timing. No additional measurement trigger is required. Non-matching
"UE Signal Info" settings generally result in large EVM results.
3.1.3 Defining the Scope of the Measurement
The R&S
CMW can measure up to 16 consecutive TD-SCDMA subframes (112 slots) in
a single measurement cycle and store the measurement results for each slot. The total
number of slots per measurement cycle is termed the "Measurement Length".
Within this measurement interval, two individual slots are selected for a more detailed
analysis:
●
The "Preselected Slot" is used for single slot measurements, e.g. to measure the
Adjacent Channel Leakage power Ratio (ACLR), the spectrum emissions and single
slot modulation measurements (vs. chip results).
Any uplink slot within the measurement interval can be selected.
TD-SCDMA TX Tests
