Keysight 53220A Mode D'emploi page 144

4 53220A/53230A Input Signal Conditioning
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
threshold
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.
For frequencies in this range, use the CONFigure command and turn off
auto-level by specifying an absolute threshold level. For example:
//measure a 10 Hz signal
CONF:FREQ 10, (@1)
INIT
Input coupling and threshold levels
Figure 4-5
When the signal includes a DC offset, the absolute value of a relative threshold is
a function of the input coupling (AC or DC).
144
level").
INP:IMP 50
INP:RANG 5
INP:COUP AC
INP:LEV 1
shows a scale of how relative thresholds apply to the input signal.
// measure 10 Hz signal
// set impedance to 50 ohms
// set range to 5V
// set AC coupling
// 1V threshold, turns off auto-level
// take reading
Keysight 53220A/53230A User's Guide
"Specifying an absolute