Add And Subtraction Measurement - Promax OD-514B Instruction Manual

Selection between CHOP mode and ALT mode is automatically made by the
TIME/DIV switch [18] shown in Figure 8. The 5 ms/DIV and lower ranges are used in the
CHOP mode and the 2 ms/DIV and higher ranges are used in the ALT mode. When the
CHOP push switch [41] is engaged, the two traces are displayed in the CHOP operation at
all ranges. The CHOP operation has priority over the ALT operation.

4.3.3 ADD and SUBTRACTION Measurement

Add and subtraction operations are two types of dual-channel operation in which
the two signals are combined to display a unique trace. In ADD operation the resultant trace
displays the algebraic sum of the CH1 and CH2 signals. In subtraction operation the
resultant trace displays the algebraic difference of CH1 and CH2 signals.
Set the oscilloscope as shown below for ADD operation.
1. Set oscilloscope to double-channel operation as shown in 4.3.2.
2. Make sure that VOLTS/DIV [10] and [14] selectors are set to the same position
and that VARIABLE [13] and [17] are set to CAL position. If signal levels are
very different, set both VOLTS/DIV selectors to the position that completely
displays on screen the signal with the highest amplitude.
3. Use the channel with the highest amplitude signal for triggering.
4. Set MODE selector [39] to ADD position. This way the unique resultant trace will
be the algebraic sum of the CH1 and CH2 signals. POSITION [37] or [40] can
be used to positioning the resultant trace.
5. If the peak-peak amplitude of the resultant trace is very small, turn both
VOLTS/DIV [10] and [14] selectors to increase the height of the displayed trace.
Make sure that both selectors are set to the same position.
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NOTE
If the input signals are in phase, the amplitude of the resultant trace
will be the arithmetic sum of the individual traces (for ex. 4.2 div + 1.2
div = 5.4 div). If the phase difference of the input signals is 180º, the
resultant amplitude is the arithmetic difference (fore ex. 4.2 div – 1.2
div = 3.0 div).
OD-514B, OD-515B & OD-545B INSTRUCTION MANUAL
Figure 8.-
November 2000