Specifications

5-27
System Command Reference Section
Error Detector DATA IN
this value and the center of the eye can be found by querying the data delay value. If
unsuccessful, the EYE:WIDth? will return NAN (Not-A-Number). The command
:TCENter|:TCENtre OFF aborts a previously started search.
NOTE The clock/data align feature (used to center the sampling point in the
data input eye) uses information derived from the input clock
frequency.
For the clock/data align feature to work properly the input frequency
must be stable during the measurement. The frequencies at the start and
end of the measurement are compared and if they differ by more than
10% the measurement fails.
When a source clocking the instrument changes frequency it will take
time for the instrument to sense the change and adjust its configuration.
Refer to the section on page 9-2 dealing with clock stabilization to
ensure that the instrument's configuration has stabilized following any
change of frequency prior to performing a clock to data alignment.
There is no need to alter the sync-mode before or after a clock to data
alignment procedure as AUTO sync-mode is automatically configured
for the duration of the procedure.
The command :TCENter|:TCENtre is an overlapped command.
SENSe[1]:EYE:ACENter ONCE|<boolean>
:ACENter ONCE
:ACENtre ONCE
:ACENter ON
:ACENtre ON
Any of the above commands initiates a search for the zero-to-one threshold voltage
midway between the two zero-to-one threshold voltages with a measured BER just in
excess of the BER configured by the EYE: THReshold command. If successful, the
command leaves the zero-one-threshold at this value and the center of the eye can be
found by querying the zero-one-threshold value. If unsuccessful, the EYE:HEIGht? will
return NAN (Not-A-Number).
The command :ACENter|:ACENtre OFF aborts a previously started search.
The command :ACENter|:ACENtre is an overlapped command.
SENSe[1]:EYE:WIDTh? <NR3>
This command interrogates the eye width found by the most recent search for the value of
data/clock delay that put the active edge in the center of the data eye.
If the result is not available or the search was unsuccessful, then the number 9.91 x E+37
(Not-A-Number, NAN) will be returned.