User`s guide

53220A/53230A User’s Guide 133
53220A/53230A Input Signal Conditioning 4
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) // measure 10 Hz signal
INP:IMP 50 // set impedance to 50 ohms
INP:RANG 5 // set range to 5V
INP:COUP AC // set AC coupling
INP:LEV 1 // 1V threshold, turns off auto-level
INIT // take reading
Input Coupling and Threshold Levels
Figure 4-5 shows a scale of how relative thresholds apply to the input signal.
When the signal includes a DC offset, the absolute value of a relative threshold
is a function of the input coupling (AC or DC).
Figure 4-5. Input Coupling and Relative Threshold Levels.
For example, a 3 Vpp input signal with a 2 VDC offset and DC coupling would
have a Vmax: value of 3.5V and a Vmin value of 0.5V (Vmax, Vmin, and Vpp are
viewable on the front panel). With AC coupling, Vmax and Vmin would be
+
1.5V respectively.
AC coupling
DC coupling
0%
100%
100%
0%
0V
(
Vmax:)
(Vmin:)
(Vmax:)
(Vmin:)