Agilent Technologies 53230A Guia do Utilizador descarregar pdf (Página 132)

132 53220A/53230A User’s Guide

4 53220A/53230A Input Signal Conditioning

INPut[{1|2}]:LEVel[{1|2}]:RELative {<percent>|MINimum|MAX-

imum|DEFault}

INPut[{1|2}]:LEVel[{1|2}]:RELative? [{MINimum|MAXimum|

DEFault}] (query form)

Threshold values are from 10% to 90% with 5% resolution. In order to specify

a relative threshold level, auto-level must be enabled.

LEVel/LEVel1 sets the relative threshold for all measurements except

rise/fall time and single-channel time interval. For rise/fall time measure-

ments, LEVel/LEVel1 sets the lower reference and LEVel2 sets the upper

reference. For single-channel time interval, LEVel/LEVel1 sets the relative

threshold for the start event and LEVel2 sets the threshold for the stop event.

CONFigure and MEASure set the threshold to 50% and enable auto-leveling.

A reset (*RST) or front panel preset (Preset) also sets the threshold to 50% and

enables auto-leveling.

Relative Threshold Example

//set a relative trigger threshold

CONF:FREQ 1E6, 0.1, (@1) // measure 1 MHz signal

INP:IMP 50 // set impedance 50 ohms

INP:RANG 5 // set range to 5V

INP:COUP AC // set AC coupling

INP:LEV:REL 30 // threshold level at 30%

Measuring Low Frequency Signals

For all counter functions, auto-level should not be used for frequencies

< 50 Hz. Threshold levels should be set using absolute values (see “Specifying

an Absolute Threshold Level”) .

The MEASure command should not be used with frequencies less than 50 Hz

as the command configures the counter (including enabling auto-level) and

makes an immediate measurement.

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Agilent Technologies 53230A Guia do Utilizador Página 132