:MEASure:AMPLitude:Q

Meas. mode:
Jitter
Package License:
L-RND
Waveform type:
NRZ
PAM4
Flex Apps:
FlexDCA
Q Commands

Command Syntax

:MEASure:AMPLitude:Q

Query Syntax

:MEASure:AMPLitude:Q?

Description

Displays the measurement if it is not already shown on the table. The query form of the command returns the measured value. Moves the Q measurement to the top of the Amplitude table. This measurement can be made on PAM4 waveforms. See the sidebar in this topic. On PAM4 signals, use the :MEASure:AMPLitude:Q:EYE command to select returning the measurement on one of three possible eyes (Eye 0/1, Eye 1/2, or Eye 2/3).

PAM4 Waveform?

For PAM4 waveforms, use this recommended (identical algorithm) command instead:

NRZ Waveform

PAM4 Waveform

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:AMPLitude:Q:

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

Child commands for measurement identification:

  • :MEASure:AMPLitude:Q:SOURce

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

Example Command Sequence

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

Measurement Ready?

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

if ('CORR' in Flex.query(':MEASure:AMPLitude:Q:STATus?')):
	measurement = Flex.query(':MEASure:AMPLitude:Q?')

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:AMPLitude:Q:COUNt?). The technique uses the :COUNt? common measurement query. For example,

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

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?.