Instrument Functions
R&S
®
FSVA/FSV
503Operating Manual 1176.7510.02 ─ 09
changed, a connection protocol is executed, and before the first measurement, a
PRBS descewing test is performed. Information on the connection status and the
results of the connection tests are provided in the "Digital IQ Info" dialog box, see
Chapter 3.7.5, "Interface Status Information", on page 513.
Measurement Settings
The "Full Scale Level" defines the level that should correspond to an I/Q sample with
the magnitude "1" and can be defined either in dBm or Volt (see "Full Scale Level"
on page 430). When converting the measured power into dBm, an impedance of 50 Ω
is assumed.
Processing digital input
The digital input signal is brought to the desired sample rate using a downsampling fil-
ter and fractional resampling. The word length of the data is 18 bits fixed point for each
I and Q. The resulting data can be processed by the selected application (see Chap-
ter 3.7.1, "Typical Applications for the R&S Digital I/Q Interface", on page 500). As
illustrated in Figure 3-36, the sample rate is dependant on the input sample rate.
Figure 3-36: Signal path using digital input
Sample rates, bandwidths and other limitations
The calculation of the usable I/Q bandwidth for active digital input is described in
Table 3-14.
Abbreviations
The following abbreviations are used in this section:
●
SR: sample rate: the sample rate that is defined by the user (e.g. in the "Data Aqui-
sition" dialog box in the "I/Q Analyzer" mode, see "Sample Rate" on page 446)
●
ISR: Input sample rate: the sample rate of the data provided by the connected
device to the digital input
●
Ms: 1 Ms = 1024 * 1024 samples
Instrument Functions - R&S Digital I/Q Interface (Option R&S
FSV-B17)
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