Instrument Function
R&S
®
SMU200A
186Operating Manual 1007.9845.32 ─ 15
The length of the signal is too short for a complete PRBS sequence; PRBS generation
is restarted by the "Restart" signal when the signal begins anew.
"On"
The reset signal for the BER measurement is fed via the "Restart" input
of the BERT interface.
If the PRBS cannpt be continued uninterruptedly, the BER measurement
must be stopped at the end of the data sequence and subsequently
restarted at the beginning of the new data sequence. The measurement
is stopped and started via a 0-1-0 slope of the restart signal. A transition
from logic 0 to 1 causes a partial result to be generated and the mea-
surement to be stopped. A transition from 1 to 0 starts the measurement
for the next subinterval. This measurement is synchronized anew.
If the R&S Signal Generator is used as a data source, a signal in which
a single 1 was coded at the end of the data sequence can be used as a
restart signal at the R&S Signal Generator marker output. This causes
the BER measurement to stop briefly at the end of the data sequence
and start again.
Partial results (number of data and error bits) are added up until the pre-
defined total number of data or error bits is reached or exceeded.
The measurement is reset by "Pattern Ignore" or "Data Enable", regard-
less of its status.
"Off"
The reset signal for the BER measurement is generated internally.
This setting is suitable for PRBS sequences that run continuously and
thus ensure uninterrupted repetition.
SCPI command:
:BERT:SETup:RESTart:STATe on page 519
Data Enable
Activates/deactivates the use of the "Data Enable" signal and sets the polarity of this
signal if it is used.
The "Data Enable" signal marks the data that is actually to be evaluated for the BER
measurement. Any data in addition to the PRBS sequence is masked and thus not eval-
uated (e.g. sync, preambles, other channels, etc that are present in the data bits supplied
by the DUT).
The signal is fed in at the "Data Enable" input of the BERT interface. It is generated by
the DUT but can also be provided by the R&S Signal Generator in the form of a marker
signal.
Note: If the data is not enabled, the BER measurement is stopped completely. The iden-
tification circuit for "Pattern Ignore" as well as the PRBS generator of the BER measure-
Bit and Block Error Rate Measurements - BERT Block
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