General Description
R&S
®
CMW-KN5xx
12
User Manual 1176.7690.02 ─ 05
For that reason all 10 subframes of a radio frame are evaluated for FDD downlink sig-
nals. For TDD signals the first 10 downlink subframes of two consecutive radio frames
are evaluated (with uplink and special subframes in-between).
The statistic count (i.e. the length of a single shot) is configurable. By default it equals
10 subframes. If you configure a different statistic count, then 10 consecutive downlink
subframes are captured repeatedly, until the statistic count is reached. Between these
repetitions there may be not captured radio frames. Up to 1000 subframes can be cap-
tured per single shot.
Example:
Statistic count = 5 subframes: 10 consecutive downlink subframes are captured.
Results are provided for the first 5 subframes.
Statistic count = 17 subframes: 10 consecutive downlink subframes are captured and
results are provided. The subsequent radio frame(s) may be ignored. Then 10 consec-
utive downlink subframes are captured. Results are provided for the first 7 subframes.
3.4 Trigger Modes
The "LTE eNodeB Multi Evaluation" measurement can be performed in the following
trigger modes:
●
Free Run (Fast Sync): The measurement starts immediately after it is initiated. The
R&S
CMW decodes the signal to derive its slot, subframe and frame timing so that
the measurement can start at a radio frame boundary.
●
Free Run (No Sync): The measurement starts immediately after it is initiated, with-
out any synchronization.
This trigger mode is faster than the "Free Run (Fast Sync)" mode. It can be used
for ACLR and emission mask measurements. All other results must be ignored
(e.g. modulation results).
●
IF Power: With an internal IF power trigger, the measurement is triggered by the
power ramp of the received bursts. This mode can for example be used for TDD
downlink signals, which are always bursted because of the uplink subframes.
●
External Trigger A/B: External trigger signal fed in via TRIG A or TRIG B on the
rear panel of the instrument. The trigger signal must be aligned to the radio frame
boundary.
●
Additional trigger modes: Other firmware applications, e.g. the GPRF generator,
may provide additional trigger modes. Refer to the documentation of the corre-
sponding firmware application for a description of these trigger modes. The trigger
signal/marker must be aligned to the radio frame boundary.
chapter 4.2.5, "Trigger Settings"
Trigger Modes
深圳德标仪器
135-1095-0799
