R&S ESR Series, Руководство пользователя

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Spectrum Measurements
R&S
®
ESR
244 User Manual 1175.7068.02 ─ 12
Remote command:
[SENSe:]SWEep:TIME
on page 835
Fast ACLR (On/Off) ← Ch Power ACLR
Switches between the IBW method ("Fast ACLR Off") and the zero span method ("Fast
ACLR On").
When switched on, the R&S ESR sets the center frequency consecutively to the differ-
ent channel center frequencies and measures the power with the selected measure-
ment 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). For details on available channel filters see
Chapter 6.2.6.3, "Selecting the
Appropriate Filter Type" , on page 366.
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 out-
put in dBm, the powers of the adjacent channels in dBm.
The sweep time is selected depending on the desired reproducibility of results. Repro-
ducibility 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 if their time interval cor-
responds 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 non-correlated. A measurement time of 40 ms is
thus required per channel for 1000 measured values. This is the default sweep time
which the R&S
ESR 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.
Remote command:
[SENSe:]POWer:HSPeed
on page 747
Set CP Reference ← Ch Power ACLR
Defines the currently measured channel power as the reference value if channel power
measurement is activated. The reference value is displayed in the "Tx1 (Ref) Power"
field; the default value is 0 dBm.
The softkey is available only for multi carrier ACLR measurements.
In adjacent-channel power measurement with one or several carrier signals, the power
is always referenced to a transmission channel, i.e. no value is displayed for "Tx1 (Ref)
Power".
Remote command:
[SENSe:]POWer:ACHannel:REFerence:AUTO ONCE
on page 736
User Standard ← Ch Power ACLR
Opens a submenu to configure customized standards.
Measurements