Measurements
R&S
®
FSW
154
User Manual 1173.9411.02 ─ 19
Channel Power Levels 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
obtain the signal to noise ratio.
Remote command:
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:
Setting a Fixed Reference for Channel Power Measurements (Set CP Reference)
For pure channel power measurements (no adjacent channels defined) with only one
Tx channel, 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.
Note:
In adjacent-channel power measurement, the power is always referenced to a
transmission channel (see
on page 152), thus, this function is not
available.
Remote command:
Optimized Settings (Adjust Settings)
All instrument settings for the selected channel setup (channel bandwidth, channel
spacing) can be optimized automatically.
The adjustment is carried out only once. If necessary, the instrument settings can be
changed later.
The following settings are optimized by "Adjust Settings":
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Channel Power and Adjacent-Channel Power (ACLR) Measurement
