Ronde & Schwarz 1304.0004.03, User Manual

Page: 137 / 1076

The Spectrum Application (RF Measurements)
R&S
®
FPL1000
137 User Manual 1178.3370.02 ─ 09
Selected Trace
The CP/ACLR measurement can be performed on any active trace.
Remote command:
[SENSe:]POWer:TRACe
on page 633
Absolute and Relative Values (ACLR Mode)
The powers of the adjacent channels are output in dBm or dBm/Hz (absolute values),
or in dBc, relative to the specified reference Tx channel.
"Abs" The absolute power in the adjacent channels is displayed in the unit
of the y-axis, e.g. in dBm, dBµV.
"Rel" The level of the adjacent channels is displayed relative to the level of
the transmission channel in dBc.
Remote command:
[SENSe:]POWer:ACHannel:MODE
on page 653
Channel power level and density (Power Unit)
By default, the channel power is displayed in absolute values. If "/Hz" is activated, the
channel power density is displayed instead. Thus, the absolute unit of the channel
power is switched from dBm to dBm/Hz.
Note: The channel power density in dBm/Hz corresponds to the power inside a band-
width of 1 Hz and is calculated as follows:
"channel power density = channel power – log
10
(channel bandwidth)"
Thus you can measure the signal/noise power density, for example, or use the addi-
tional functions
Absolute and Relative Values (ACLR Mode) and Reference Channel to
obtain the signal to noise ratio.
Remote command:
CALCulate<n>:MARKer<m>:FUNCtion:POWer<sb>:RESult:PHZ
on page 653
Power Mode
The measured power values can be displayed directly for each trace ("Clear/ Write"),
or only the maximum values over a series of measurements can be displayed ("Max
Hold"). In the latter case, the power values are calculated from the current trace and
compared with the previous power value using a maximum algorithm. The higher value
is retained. If "Max Hold" mode is activated, "Pwr Max" is indicated in the table header.
Note that the
trace mode remains unaffected by this setting.
Remote command:
CALCulate<n>:MARKer<m>:FUNCtion:POWer<sb>:MODE
on page 630
Setting a fixed reference for Channel Power measurements (Set CP Reference)
If only one Tx channel and no adjacent channels are defined, the currently measured
channel power can be used as a fixed reference value for subsequent channel power
measurements.
When you select this button, the channel power currently measured on the Tx channel
is stored as a fixed reference power. In the following channel power measurements,
the power is indicated relative to the fixed reference power. The reference value is dis-
played in the "Reference" field (in relative ACLR mode); the default value is 0 dBm.
Measurements and Results