:MEASure:PEYE:SERFloor?
Command Syntax
:MEASure:PEYE:SERFloor
Query Syntax
:MEASure:PEYE:SERFloor?
Description
For a PAM4 waveform, displays a SER floor measurement in the Eye table. If the measurement is already listed, the measurement is moved to the top of the table. Use the query form of the command to return the measured value. To select the eye in the PAM4 eye diagram on which to return the measurement, use the :MEASURE:PEYE:SERFloor:EYE command. The measurement can be performed on one of three possible eyes as shown in the following picture: Eye 0/1, Eye 1/2, or Eye 2/3.
The measured SER is the extrapolated SER at the center of the eye. If both amplitude and jitter analysis is active, it will take into account both the probability of timing errors (jitter) as well as the probability of amplitude errors (noise and interference). SER Floor is the predicted SER at intersection of the jitter and amplitude measurement locations within the eye. It accounts for both horizontal eye closure (jitter) and vertical eye closure (noise and interference). The SER floor is calculated by extrapolating the amplitude bathtub curve to the jitter measurement location and extrapolating the jitter bathtub curve to the amplitude measurement location. These floors are then added together to form the SER floor. If the floor is below 10−18, the signal is considered error free.
| Select | Command |
|---|---|
| Signal eye | :MEASure:PEYE:SERFloor:EYE
|
Amplitude analysis must be turned on before the first interference measurement can be made. Use the :MEASure:AMPLitude:DEFine:ANALysis command.
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:PEYE:SERFloor?:
flex.write(':MEASure:PEYE:SERFloor?:SOURce CHAN1A')
if flex.query(':MEASure:PEYE:SERFloor?:STATus?') == 'CORR';
measurement = flex.query(':MEASure:PEYE:SERFloor??')
else:
details = flex.query(':MEASure:PEYE:SERFloor?:STATus:DETails?')
reason = flex.query(':MEASure:PEYE:SERFloor?:STATus:REASon?')
Child commands for measurement identification:
:MEASure:PEYE:SERFloor?:SOURce
Requires FlexDCA revision A.06.00 and above.
Example Command Sequence
:MEASure:PEYE:DEFine:ANALysis ON :MEASure:PEYE:SERFloor:SOURce CHAN1A :MEASure:PEYE:SERFloor :MEASure:PEYE:SERFloor?
Measurement Ready?
To confirm that the measurement is ready to read, you can query the measurement's status:
if ('CORR' in Flex.query(':MEASure:PEYE:SERFloor?:STATus?')):
measurement = Flex.query(':MEASure:PEYE:SERFloor??')
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:PEYE:SERFloor?:COUNt?). The technique uses the :COUNt? common measurement query. For example,
if (Flex.query(':MEASure:PEYE:SERFloor?:COUNt?') >= Flex.query(':ACQuire:ECOUNt?')):
measurement = Flex.query(':MEASure:PEYE:SERFloor??')
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?.