# :MARKer:REFerence

:MARKer Tracking Commands

- :MARKer:X:POSition
- :MARKer:X:SOURce
- :MARKer:X:SOURce:DUT
- :MARKer:X:SOURce:SPARameter
- :MARKer:X:SOURce:TYPE
- :MARKer:Y:SOURce
- :MARKer:Y:SOURce:DUT
- :MARKer:Y:SOURce:SPARameter
- :MARKer:Y:SOURce:TYPE
- :MARKer:Y:STATe
- :MARKer:REFerence

:MARKer Manual-Line Commands

- :MARKer:X:POSition
- :MARKer:X:STATe
- :MARKer:Y:POSition
- :MARKer:Y:STATe
- :MARKer:REFerence

## Command Syntax

    :MARKer:REFerence {X1 | X2 | X3 | X4}

## Query Syntax

    :MARKer:REFerence?

## Description

Selects the tracking marker or manual line marker that is used as the reference marker for delta marker measurements. For manual line markers:

- If both 1, 2, 3, or 4 markers are on (for example, X1 and Y1), making either marker the reference makes both markers a reference for markers on their graph axis.
- If only one of the 1, 2, 3, or 4 markers are on (for example, X1 but not Y1) only part of the delta measurements are available. For example, if X2 is on and Y2 is off, only the ΔX and not the ΔY measurements can be made.

To return the delta measurements, use the following :MEASure subsystem queries:

- `:MEASure:MARKer:DX?`
- `:MEASure:MARKer:DY?`
- `:MEASure:MARKer:IDX?`

## Example Command Sequence

This example illustrates how to use all of the marker related commands and, as a result, is not presented as a best measurement practice. The example uses a tracking marker pair, manual line X marker, and manual line Y marker. Because a tracking marker pair is used, the waveforms must be single-valued. You could also turn on two tracking markers and read the delta values between them.

                      //  Configure Manual Line Marker X1
    :MARKer:X1:STATe MANual  //  Turn on marker
    :MARKer:X1:SOURce CHAN1_1  //  Assign marker to connection 1 channel 1 waveform
    :MARKer:X1:POSition 80E-12  //  Position marker to 80 ps
                      //  Configure Manual Line Marker Y1
    :MARKer:Y1A:STATe MANual  //  Turn on Y manual line marker 1.
    :MARKer:Y1A:SOURce CHAN1_1  //  Assign marker to connection 1 channel 1 waveform
    :MARKer:Y1A:POSition 120E-3  //  Position marker to 120 mv
    :MARKer:REFerence X1  //  Set markers X1 and Y1 as the reference
                      //  Configure Tracking Marker Pair 2
    :MARKer:Y2A:STATe TRACking  //  Turn on marker
    :MARKer:X2:SOURce FUNCtion3  //  Assign marker to FUNCtion3 waveform
    :MARKer:X2:POSition 200E-12  //  Position marker on screen

    …  //  Prompt tester to position marker on the waveform
                      //  Return Marker Table Measurements for Tracking Marker 2
    :MEASure:MARKer:DX2?  //  Return ΔPosition

    :MEASure:MARKer:IDX2?  //  Return inverse of ΔPosition

    :MEASure:MARKer:DY2A?  //  Return ΔMagnitude

    :MEASure:MARKer:Y2A?  //  Return Y2 Magnitude