:MEASure:AMPLitude:BERLimit

Deprecated command. For FlexDCA revision A.05.60 and above, use the :MEASure:AMPLitude:SERLimit command instead.

Command Syntax

:MEASure:AMPLitude:BERLimit

Query Syntax

:MEASure:AMPLitude:BERLimit?

Description

For NRZ measurements, moves the BER limit measurement to the top of the Amplitude table. For PAM4 measurements, moves the BER floor measurement to the top of the Eye table. Displays the measurement if it is not already shown on the table. The query form of the command returns the state of BER limiting.

The query returns a string that reports whether the signal is limited by jitter, amplitude (noise and interference), or equally jitter and amplitude. BER limit indicates if the eye will close vertically before it closes horizontally or vice-versa. The BER limit is determined by extrapolating both the Jitter and Amplitude bathtub curves down to their respective BER floors. If the BER floors are within 10% (on a log scale) of each other, the system is considered balanced. If not, the limiting impairment is the one with the higher floor. If both BER floors are ≤ 1E-18, the BER limit cannot be determined and is listed in the Amplitude table as "Not Limited".

On PAM4 signals, the BER limiting state can be checked on one of three possible eyes as shown in the following picture: Eye 0/1, Eye 1/2, or Eye 2/3.

NRZ Waveform
PAM4 Waveform

Requires option 200 (Enhanced Jitter Analysis) and option 300 (Advanced Amplitude Analysis/RIN/Q-Factor). For PAM4 signals requires additional option 9TP (PAM-N Analysis).

Query Response

AMPL
Signal is limited by noise/interference.
JITT
Signal is limited by jitter.
BAL
Signal is limited by a balanced contribution of both jitter and noise/interference.
NLIM
The signal is not limited by jitter or noise/interference.

Requires Jitter Mode with additional Advanced Amplitude Analysis/RIN/Q-Factor license .

Amplitude analysis must be turned on before the first interference measurement can be made. Use the :MEASure:AMPLitude:DEFine:ANALysis command.

For FlexDCA revision A.01.70 and above, this command displays and returns a status string instead of a statistical value.

Example Command Sequence

:MEASure:AMPLitude:DEFine:ANALysis ON
:MEASure:AMPLitude:BERLimit:SOURce CHAN1A
:MEASure:AMPLitude:BERLimit
:MEASure:AMPLitude:BERLimit?

Common Measurement Child Queries

Common measurement queries. :COUNt?, :LOCation?, :MAXimum?, :MINimum?, :MEAN?, and :SDEViation?.