Rohde & Schwarz SMU200A - LEVEL OFFS: Rmsoffset_Db,Peakoffset_Db

Remote Control Commands
R&S
®
SMU200A
501Operating Manual 1007.9845.32 ─ 15
{CONTROL LENGTH: 444}
BB:ARB:WAV:TAG? 'CONTROL LENGTH'
queries the length of the control list.
Response: '444'
Example:
Setting onlyUsage:
{LEVEL OFFS: RMSOffset_dB,PeakOffset_dB}
(recommended for waveforms)
The tag determines the level of the ARB signal in the waveform file. The offset levels
define the offset of rms and peak value relative to the 16-bit full scale modulation (-32767
to + 32767) = 0 dB.
Setting parameters:
Defines the RMS level offset of the signal relative to full scale ARB
signal in the WAVEFORM tag. The offset is defined in ASCII float
format. The value is always positive.
A 3dB value indicates that the RMS level of the signal is 3 dBs
below the full scale.
full scale = max. amplitude of vector of I/Q samples = |S
IQ
|max =
sqrt(I
2
+Q
2
)max = 0 dB
Defines the peak level offset of the signal relative to full scale for
the ARB signal in the WAVEFORM tag. The offset is defined in ASCII
float format.
The value usually equals 0 dB as in the majority of cases the I/Q
samples (signed 16-bit integer values) are modulated to full scale:
Full scale = 0 dB = max. amplitude of vector of I/Q samples = |
S
IQ
|max = sqrt(I
2
+Q
2
)max = (2
15
)-1 = 32767.
A positive PeakOffset_dB value indicates that a headroom to
full scale is provided when generating the waveform. A negative
PeakOffset_dB value indicates that overrange is likely for some
samples, i.e. clipping might occur.
The crest factor can be calculated from the two values as follows:
Crest Factor = |PeakOffset_dB - RMSOffset_dB|
RMSOffset_dB
PeakOffset_dB
{LEVEL OFFS: 3.45,2}
BB:ARB:WAV:TAG? 'LEVEL OFFS'
queries the content of the 'LEVEL OFFS' tag of the selected wave-
form file.
Response: '3.45,2'
the level of the waveform is below full scale, clipping will not occur.
Example:
Setting onlyUsage:
R&S Signal Generator Waveform and List Format