1. Roll mode:

Roll mode is the most useful mode and has been available on digital storage oscilloscopes (DSO) from the earliest stage. It is fundamentally different from a conventional scope display and it leads in nicely to the other operating modes of digital storage oscilloscopes. This mode is used to display very fast varying signals, clearly on the screen. The fast varying signal is displayed as if it is changing slowly, on the screen. In this mode, the input signal is not triggered at all. The stored signal is rolled slowly from right to left across the screen.

1. Refresh mode:

This is the most commonly used mode. In this mode, the input initiates a trigger circuit. This initiates the memory write cycle. The digital data is transferred to the memory. When the memory is full, the write cycle stops. Using digital to analog converter, the memory data is converted to analog and then displayed on the screen. When the next trigger occurs the memory is refreshed.

1. Single Shot mode or Save Mode:

This is also called automatic refresh mode. When new sweep signal is generated by time base generator, the old contents get overwritten by new one. If a particular signal is to be stored then by pressing hold or save button, overwriting can be stopped and previously saved signal is locked.

Single shot events, such as the waveform of an explosion are transient in nature and are lost very quickly. The observer cannot see such events, unless the waveform is photographed or stored. Such events can be stored in memory of digital storage oscilloscope and reading the memory rapidly and repetitively the continuous waveform can be obtained.