I/Q Analyzer
R&S
®
ESR
474
User Manual 1175.7068.02 ─ 12
Figure 7-1: Block diagram illustrating the R&S
ESR signal processing
Maximum number of samples
The maximum number of samples for RF input is 200 MS.
7.5.1
Sample Rate and Maximum Usable Bandwidth (RF Input)
Definitions
●
Input sample rate (ISR)
: the sample rate of the useful data provided by the con-
nected instrument to the R&S
ESR input
●
(User, Output)
Sample rate (SR)
: the sample rate that is defined by the user (e.g.
in the "Data Aquisition" dialog box in the "I/Q Analyzer" application) and which is
used as the basis for analysis or output
●
Usable I/Q (Analysis) bandwidth
: the bandwidth range in which the signal
remains undistorted in regard to amplitude characteristic and group delay; this
range can be used for accurate analysis by the R&S
ESR
For the I/Q data acquisition, digital decimation filters are used internally. The passband
of these digital filters determines the
maximum usable I/Q bandwidth
. In consequence,
signals within the usable I/Q bandwidth (passband) remain unchanged, while signals
outside the usable I/Q bandwidth (passband) are suppressed. Usually, the suppressed
signals are noise, artifacts, and the second IF side band. If frequencies of interest to
you are also suppressed, you should try to increase the output sample rate, since this
increases the maximum usable I/Q bandwidth.
Relationship between sample rate and usable bandwidth
shows the maximum usable I/Q bandwidths depending on the
user sample rates.
As a rule, the usable bandwidth is proportional to the output sample. Yet, when the I/Q
bandwidth reaches the bandwidth of the analog IF filter (at very high sample rates), the
curve breaks.
Working with I/Q Data
