:MEASure:EYE:TTIMe

Meas. mode:
Eye
Package License:
L-RND
Waveform type:
NRZ
PAM4
Flex Apps:
FlexDCA
FlexRT
PAM Transition Time Commands

Command Syntax

:MEASure:EYE:TTIMe

Query Syntax

:MEASure:EYE:TTIMe?

Description

The Eye/Mask mode IEEE 802.3cd PAM Transition Time measurement measures the transition time on PAM4 waveforms. The query form of the command returns the selected transition time measured. Use the :MEASure:EYE:TTIMe:TRANsition child command to select from three available transition time measurements:

  • Slowest edge
  • Average rising edge
  • Average falling edge

By default, measurements are made on the following edges:

  • Rising edges: A run of at least 5 level zeros, leading Consecutive Identical Digits (CIDs), and 6 level threes, lagging CIDs.
  • Falling edge: A run of at least 5 level threes, leading Consecutive Identical Digits (CIDs) and 6 level zeros, lagging CIDs

The transition time is measured as the waveform's edge transitions through the 20% to 80% amplitude levels between the average level zero and average level three. The average level amplitudes are measured using the same algorithm as is used for the Outer OMA measurement (:MEASure:EYE:OOMA).

You can change the default minimum leading and lagging CIDs with these commands:

Before making this measurement, apply a System Impulse Response Correction (SIRC) data digital filter (Option IRC on N1092A, 86105C, 86105D, 86115D, or 86116C modules). Use the :CHANnel:SIRC and :CHANnel:SIRC:FRATe commands. This is the same filter that is used with the TDECQ (Transmitter and Dispersion Eye Closure Quaternary) measurement (:MEASure:EYE:TDEQ).

Requires FlexDCA revision A.06.00 and above.

Measurement Identification

Avoid subtle programming errors! To ensure that the correct measurement is installed or queried, always explicitly identify a measurement when installing a measurement or querying a measured value, status, or detail. To identify a measurement, specify the measurement's source waveform (:SOURce child command). With some measurements, you may also need to specify other identifying values. Generally, when selecting a measurement using FlexDCA's GUI, if a dialog appears prompting you to select values, you should explicitly specify these values when remotely identifying the measurement. More information.

For example, to return the status of the measurement, :MEASure:EYE:TTIMe:

flex.write(':MEASure:EYE:TTIMe:SOURce CHAN1A')
if flex.query(':MEASure:EYE:TTIMe:STATus?') == 'CORR';
    measurement = flex.query(':MEASure:EYE:TTIMe?')
else:
	details = flex.query(':MEASure:EYE:TTIMe:STATus:DETails?')
	reason = flex.query(':MEASure:EYE:TTIMe:STATus:REASon?')

Child commands for measurement identification:

  • :MEASure:EYE:TTIMe:SOURce
  • :MEASure:EYE:TTIMe:TRANsition

Measurement Ready?

To confirm that the measurement is ready to read, you can query the measurement's status:

if ('CORR' in Flex.query(':MEASure:EYE:TTIMe:STATus?')):
	measurement = Flex.query(':MEASure:EYE:TTIMe?')

If averaging is turned on (:ACQuire:AVERaging), you can also confirm if the measurement result is ready by comparing the number of specified averages (:ACQuire:ECOunt?) versus the number of measurement sweeps that have occurred (:MEASure:EYE:TTIMe:COUNt?). The technique uses the :COUNt? common measurement query. For example,

if (Flex.query(':MEASure:EYE:TTIMe:COUNt?') >= Flex.query(':ACQuire:ECOUNt?')):
	measurement = Flex.query(':MEASure:EYE:TTIMe?')

You can also use an acquisition limit lest to test that a number of waveform samples, or pattern acquisitions have completed before returning a measurement. Refer to the :LTESt:ACQuire:CTYPe command.

Common Measurement Child Queries

This command supports the use of the following common measurement queries: :LOCation?, :COUNt?, :MAXimum?, :MINimum?, :MEAN?, and :SDEViation?.