Rohde & Schwarz R&S SMW200A - Page 226

Configuring the Internal Baseband Source
R&S
®
SMW200A
226User Manual 1175.6632.02 ─ 30
PRBS generator Length in bits Feedback to GUI selection
20-bit
2
20
-1 = 1048575
Registers 3, 0 PRBS 20/PN20
21-bit
2
21
-1 = 2097151
Registers 2, 0 PRBS 21/PN21
23-bit
2
23
-1 = 8388607
Registers 5, 0 PRBS 23/PN23
Example:
By way of example, the diagram on A 9-bit PRBS generator shows a 9-bit generator
with feedback to registers 4 and 0 (output). The generated serial data is converted
internally, e.g 2 Bit/Symbol if QPSK is used.
Figure 5-1: A 9-bit PRBS generator
Related settings:
●
Chapter 5.6.3.3, "Data Source", on page 266
●
Chapter 5.6.3.7, "Data List Editor", on page 279
●
Chapter 5.6.3.8, "Control and Marker Lists Editor", on page 281
●
"Data Source" selection in the dialogs of the firmware options
External Modulation Data
Option:
●
R&S SMW-B10
●
R&S SMW-B9, only in "System Config > Mode > Advanced".
The R&S SMW can generate custom digitally modulated signal form external serial
data source.
For proper synchronization, the R&S SMW requires a reference (external) symbol
clock signal to generate a bit clock out of it. The active edge of both, the symbol clock
and the bit clock, is configurable. Positive and negative timing deviations between the
clock and the data signals are indicated and automatically corrected.
Figure 5-2: Timing deviations (t_hold and t_setup) between the clock and the data signals
Common Functions and Settings in the Baseband Domain