MEAS - Analyzer R&S ESCI
1166.6004.12 4.156 E-1
FAST ACP
ON OFF
The FAST ACP softkey switches between the IBW method (FAST ACP OFF) and
the time domain method (FAST ACP ON).
With FAST ACP ON the power measurement is performed in the different channels
in the time domain. The R&S ESCI sets the center frequency consecutively to the
different channel center frequencies and measures the power with the selected
measurement time (= sweep time/number of channels). The RBW filters suitable for
the selected standard and frequency offset are automatically used (e.g. root raised
cos with IS 136). The list of available channel filters is included in section "Setting of
Bandwidths and Sweep Time – BW key".
The RMS detector is used for obtaining correct power measurement results.
Therefore this requires no software correction factors.
Measured values are output as a list. The powers of the transmission channels
are output in dBm, the powers of the adjacent channels in dBm (CP/ACP ABS)
or dB (CP/ACP REL).
The sweep time is selected depending on the desired reproducibility of results.
Reproducibility increases with sweep time since power measurement is then
performed over a longer time period.
As a general approach, it can be assumed that approx. 500 non-correlated
measured values are required for a reproducibility of 0.5 dB (99% of the
measurements are within 0.5 dB of the true measured value). This holds true for
white noise. The measured values are considered as non-correlated when their
time interval corresponds to the reciprocal of the measured bandwidth.
With IS 136 the measurement bandwidth is approx. 25 kHz, i.e. measured
values at an interval of 40 µs are considered as noncorrelated. A measurement
time of 20 ms is thus required per channel for 1000 measured values. This is the
default sweep time which the R&S ESCI sets in coupled mode. Approx. 5000
measured values are required for a reproducibility of 0.1 dB (99%), i.e. the
measurement time is to be increased to 200 ms.
IEC/IEEE-bus command SENS:POW:HSP ON
FULL SIZE
DIAGRAM
The FULL SIZE DIAGRAM softkey switches the diagram to full screen size.
IEC/IEEE-bus command: DISP:WIND1:SIZE LARG|SMAL
ADJUST
REF LVL
The ADJUST REF LVL softkey adjusts the reference level of the R&S ESCI to
the measured channel power. This ensures that the settings of the RF
attenuation and the reference level are optimally adjusted to the signal level
without overloading the R&S ESCI or limiting the dynamic range by a too small
S/N ratio.
Since the measurement bandwidth for channel power measurements is
significantly lower than the signal bandwidth, the signal path may be overloaded
although the trace is still significantly below the reference level.
IEC/IEEE-bus command: SENS:POW:ACH:PRES:RLEV
For manual setting of the test parameters different from the settings made with ADJUST SETTINGS the
following should be observed:
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