The display is blanked during the fly back and hold-off periods, as in a conventional oscilloscope. In this the electronic switch alternates between channels A and B, letting each through for one cycle of the horizontal sweep. The alternate mode is illustrated in the figure below. There are two common operating modes for the electronic switch, called alternate and chop, and these are selected from the instrument’s front panel. This textbook “ Electrical and Electronics Measurements by S. Lissajous Patterns of CRO or Cathode ray oscilloscope.Digital Storage Oscilloscope(DSO) Working Principle and its Operation.Comparison Between Cathode ray and Digital Storage Oscilloscopes.This has the ability to pass one channel at a time into the vertical amplifier, via the delay line. After preamplification, the two channels meet at an electronic switch. Therefore the amplitude of each input, as viewed on the oscilloscope, can be individually controlled. There are two separate vertical input channels, A and B, and these use separate attenuator and preamplifier stages. The figure below shows the construction & working dual trace oscilloscope. Here we are going to discuss dual trace oscilloscope whose working and construction is completely different from dual beam oscilloscope. Two input oscilloscopes are described, dual trace and dual beam. Single beam which can then be converted into several traces, and dual beam, which may also be converted into a further number of traces. Two inputs are the most common, although four and eight inputs are available for special application. Oscilloscopes can have multiple inputs and display facilities. Dual Trace Oscilloscope Working Principle:

Explain dual trace oscilloscope