Note For arm source TTLTRG<n >, the digitizer arms on the negative-going edge of the signal. For arm source ECLTrg<n >, the digitizer arms on the positive-going edge. These sources are not affected by the ARM:STARt:SLOPe command.

Arm Window The boundaries of the window are set by the voltage levels of Boundaries ARM[:STARt]:LEVel:POSitive and ARM[:STARt]:LEVel:NEGative.

When ARM[:STARt]:LEVel:POSitive specifies a level that is greater than ARM[:STARt]:LEVel:NEGative, the digitizer is armed when the input signal exits the defined window. When ARM[:STARt]:LEVel:POSitive specifies a level that is less than ARM[:STARt]:LEVel:NEGative, the digitizer is armed when the input signal enters the defined window.

Figure 3-6. Arm Window Boundaries

Setting the Arm Level When the arm source is INTernal1 or INTernal2, the level of the input signal at which the digitizer becomes armed is set with the commands:

ARM[:STARt]:LEVEL[<n >]:NEGative <voltage >

This command sets the voltage level on the specified channel that, when reached by a negative-goinginput signal, arms the digitizer.

ARM[:STARt]:LEVEL[<n >]:POSitive <voltage >

This command sets the voltage level on the specified channel that, when reached by a positive-goinginput signal, arms the digitizer.

116 Understanding the HP E1429 Digitizer

Chapter 3

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HP E1429A manual Arm Window Boundaries