Remote Control Commands
R&S
®
SMBV100A
444
Operating Manual 1407.6062.32 ─ 08
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:
RMSOffset_dB
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
PeakOffset_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|
Example:
{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.
Usage:
Setting only
{SAMPLES: Samples}
(recommended for waveforms)
The tag contains the number of I/Q samples in the waveform in ASCII format.
On multi segment waveforms, this tag contains the total I/Q samples of all segments.
Example:
{SAMPLES: 4333}
BB:ARB:WAV:TAG? 'SAMPLES'
queries the content of the
SAMPLES
tag of the selected waveform
file.
Response: '4333'
the waveform contains 4333 I/Q samples.
Usage:
Setting only
R&S Signal Generator Waveform and List Format
Summary of Contents for SMBV100A
Page 31: ......
