Agilent Technologies Agilent 33500 Series Operating And Service Manual page 110

When signals are combined, the DC Offset values are not added together. Only the DC Offset from the receiving chan-
nel is used in the combined output. The figure below shows 50 a mV DC Offset added to Channel 1. The 50 mV offset
added to Channel 2 is ignored.
Logic signal amplitudes are added in the same way as any other signal. They are not OR'd together. For example, con-
sider the signals below.
When these are combined, the amplitudes are added, as shown below. Note that the combined signal has three voltage
levels: 150 mV, 50 mV and -50 mV. This is a result of the following combinations:
CH1 +50 mV + 50 mV DC Offset, plus CH2 +50 mV signal = +150 mV.
l
CH1 -50 mV + 50 mV DC Offset, plus CH2 +50 mV signal = + 50 mV.
l
CH1 -50 mV + 50 mV DC Offset, plus CH2 -50 mV signal = -50 mV.
l
CH1 +50 mV + 50 mV DC Offset, plus CH2 -50 mV signal = +50 mV.
l
Agilent 33500 Series Operating and Service Guide
Dual Channel Operations
109