Instrument Function
R&S
®
SMBV100A
194
Operating Manual 1176.8016.02 ─ 17
"External"
The reset signal for the BER measurement is fed via the "Restart"
input of the BERT interface.
If the PRBS cannot be continued uninterruptedly, the BER measure-
ment must be stopped at the end of the data sequence and subse-
quently 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 gen-
erated and the measurement 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
SMBV 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
SMBV 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
predefined total number of data or error bits is reached or exceeded.
The measurement is reset by "Pattern Ignore" or "Data Enable",
regardless of its status.
"Internal"
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.
Remote command:
Data Enable
Activates the use of the "Data Enable" signal and sets the polarity of this signal if it is
used.
The "Data Enable" signal determines the data to be evaluated for the BER measure-
ment. Any data in addition to the PRBS sequence is masked and thus not evaluated
(e.g. sync, preambles, other channels, etc. that are present in the data bits supplied by
the DUT).
The DUT usually provides the data enable signal, but you can also use a marker signal
of R&S
SMBV.
Note:
If the data is not enabled, the BER measurement is stopped completely. The
identification circuit for "Pattern Ignore" as well as the PRBS generator of the BER
measurement wait as long as data is not enabled. If the data is enabled, the measure-
ment is continued.
"Not Used"
Any signal at the "Data Enable" input is ignored; all data at the BER
data input is used for the measurement.
"High"
The "Data Enable" signal is active. The BER tester measures all
incoming data during the high level of the "Data Enable" signal. Dur-
ing the low level, the measurement is interrupted.
"Low"
The "Data Enable" signal is active. The BER tester measures all
incoming data during the low level of the "Data Enable" signal. During
the high level, the measurement is interrupted.
Bit and Block Error Rate Measurements
