Basics on I/Q Data Acquisition and Processing
R&S
®
FSV/A3000 I/Q
Analyzer
19
User Manual 1178.8536.02 ─ 01
●
Record length
: Number of I/Q samples to capture during the specified measure-
ment time; calculated as the measurement time multiplied by the sample rate
For the I/Q data acquisition, digital decimation filters are used internally in the
R&S
FSV/A. 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, try to increase the out-
put sample rate, which increases the maximum usable I/Q bandwidth.
Bandwidth extension options
You can extend the maximum usable I/Q bandwidth provided by the R&S
FSV/A in the
basic installation by adding options. These options can either be included in the initial
installation (B-options) or updated later (U-options). The maximum bandwidth provided
by the individual option is indicated by its number, for example, B40 extends the band-
width to 40
MHz.
As a rule, the usable I/Q bandwidth is proportional to the output sample rate. Yet, when
the I/Q bandwidth reaches the bandwidth of the analog IF filter (at very high output
sample rates), the curve breaks.
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Relationship Between Sample Rate, Record Length and Usable I/Q Bandwidth
FSV/A Without Additional Bandwidth Extension Options
............................... 20
FSV/A with I/Q Bandwidth Extension Option B40 or U40
...............................20
FSV/A with I/Q Bandwidth Extension Option B200 or U200
FSV/A with I/Q Bandwidth Extension Option B400 or U400
4.1.1.1
Bandwidth Extension Options
Max. usable I/Q BW
Required B-option
40 MHz
B40
200 MHz
B200
400 MHz
B400
4.1.1.2
Relationship Between Sample Rate, Record Length and Usable I/Q Bandwidth
Up to the maximum bandwidth, the following rule applies:
Usable I/Q bandwidth = 0.8 * Output sample rate
Regarding the record length, the following rule applies:
Record length = Measurement time * sample rate
Processing Analog I/Q Data from RF Input