# :MEASure:VERTical:VTOP

Waveform Top Commands

- :MEASure:VERTical:VTOP
- :MEASure:VERTical:VTOP:FAVorite
- :MEASure:VERTical:VTOP:LOCation?
- :MEASure:VERTical:VTOP:REGion
- :MEASure:VERTical:VTOP:SOURce
- :MEASure:VERTical:VTOP:STATus?
- :MEASure:VERTical:VTOP:STATus:DETails?
- :MEASure:VERTical:VTOP:STATus:REASon?
- :MEASure:VERTical:VTOP:UREFerence:STATe
- :MEASure:VERTical:VTOP:UREFerence:VALue

## Command Syntax

    :MEASure:VERTical:VTOP

## Query Syntax

    :MEASure:VERTical:VTOP?

## Description

Moves the Waveform Top measurement to the top of the Results table. This measurement may be compatible with PAM signals, depending on the PAM waveform. Displays the measurement if it is not already shown on the table. The query form of the command returns the measured value. Waveform Top is the most prevalent value of the upper 40% of a pulse or eye diagram. Sources can be any displayed waveform, waveform memory, or function. For example, CHAN1_1, WMEMory1, or FUNCtion1. Use `:MEASure:TBASe:GENeral:METHod` to change the definition of the waveform's top/base. Use `:<waveform>:THReshold:GENeral:METHod` to change the definition of the waveform's threshold.

PAM Compatibility. Because this measurement is based on waveform top and base levels and the passing of the waveform's edge through lower, middle, and upper thresholds, the measurement is not designed for PAM signals. However, the measurement may be able to be made on PAM signals if the waveform top and base definitions are manually set. This can be attempted using the following commands: `:MEASure:TBASe:GENeral:METHod`, `:CHANnel:THReshold:GENeral:TOP`, and `:CHANnel:THReshold:GENeral:BASE` commands.

## Example Command Sequence

    :MEASure:VERTical:VTOP:SOURce CHAN1_1
    :MEASure:VERTical:VTOP
    :MEASure:VERTical:VTOP?

## Measurement Ready?

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

    if ('CORR' in Infiniium.query(':MEASure:VERTical:VTOP:STATus?')):
    	measurement = Infiniium.query(':MEASure:VERTical:VTOP?')

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

    if (Infiniium.query(':MEASure:VERTical:VTOP:COUNt?') >= Infiniium.query(':ACQuire:COUNt?')):
    	measurement = Infiniium.query(':MEASure:VERTical:VTOP?')

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

## Querying Measurement Results and Statistics

You can query measurement results using the `:MEASure:VERTical:VTOP?` query after making the proper instance settings.

If a measurement is installed into Results table (using the `:MEASure:VERTical:VTOP` command) and you have made the proper instance settings, you can query statistics using common child queries.

Also, you can query measurement results and statistics directly from the Results table (without having to make the proper instance settings beforehand). See Querying Measurement Results and Statistics.