Rohde & Schwarz SMBV100A, Руководство по эксплуатации

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Instrument Function
R&S
®
SMBV100A
380 Operating Manual 1176.8016.02 ─ 17
The ARB generator enables the calculation and the generation of multi segment
and multi carrier waveform files as well as the build in function to create a test
waveform (e.g. a sine or rectangle signal) and keep it as a file or in the RAM.
Several digital standards provide the special function "Generate Waveform File"
and enable the calculation and storage of the signal as a waveform file that can be
afterwards processed by the ARB generator.
●
Externally generated waveforms
The ARB can also process externally generated waveform files e.g. the waveform
files generated on a PC by the Windows software package R&S
WinIQSIM2, the
software R&S ARB Toolbox, the R&S SMx-K6 Pulse Sequencer software or sig-
nals calculated using a mathematical program such as Matlab.
For more information also on the required options, refer to the Rohde&Schwarz
web site at
http://www.rohde-schwarz.com . See also the Application Note 1MA28,
“IQWizard - I/Q Signal Measurement and Conversion".
The externally generated waveform files can be loaded into the instrument via one
of the available interfaces (USB, LAN or GPIB). Usually, the waveform file is stored
on one of the network drives which are accessible for the operating system.
Playing and Streaming Waveform Files
●
Playback from the internal memory
In the most common case, the ARB generator plays back a waveform file with a
selectable clock frequency. The R&S
SMBV loads the entire file into the ARB mem-
ory from where the IQ samples are played repeatedly.
This is suitable for files of limited size, e.g. up to 128 MB for instruments equipped
with option R&S
SMBV-B10.
The maximum size for streaming and ARB files is also listed in the R&S SMBV
data sheet.
ARB Test Signals
The following test signals are available:
●
Sine Test Signal: Two sinewave signals with a selectable (but equal) number of
samples per period and equal frequencies. When the generation is triggered, the
number of samples per period, together with the frequency of the test signal, deter-
mines the ARB clock frequency: "Clock Frequency" = "Frequency" * "Samples per
Period".
Note: Because the resulting clock rate must not exceed the maximum ARB clock
rate (see data sheet), the number of sample values is automatically restricted
depending on the selected frequency.
The first sine signal is mapped on the I samples, the second on the Q samples.
The two signals differ by a selectable phase offset. For a
–
90 deg offset, the result
is a unit vector in the I/Q plane, rotating counter-clockwise and starting at I = 0, Q =
–
1. For a 0 deg offset, the I and Q samples are on the diagonal of a unit square (I(t)
= Q(t)).
Baseband Signal - Baseband Block