A digital storage oscilloscope, also known as a DSO, is an electronic device that is capable of storing a digital copy of the measured waveform. Using analog-to-digital converters to digitize and sample measured voltages, a digital storage oscilloscope stores the results in its memory, which it process further using digital signal processing techniques.

An oscilloscope is a device used for testing signal voltages in fields such as circuit debugging, electronic measurement, testing in manufacturing, designing, general testing and researches. Also known as a scope, an oscilloscope displays the changes in signal voltage over a certain period of time. It usually comes with a rectangular screen, which allows users to view the input voltage on a particular axis over a particular period of time on the other. Instead of displaying time on the other axis, the scope can also display a second signal voltage, while changing the intensity of the screen image using a third waveform allows the scope to display a three dimensional figure. Some scopes can even display multiple waveforms simultaneously, superimposed on each other or separately for comparison purposes.

Just like other kinds of digital oscilloscopes, a DSO converts analog input voltages into digital data. Two factors determine the maximum frequency that the digital storage oscilloscope can measure. One is the sampling rate of the oscilloscope, which is usually measured in millions or billions of samples per second, and the other is the nature of the analog-to-digital converter and the signal amplifier on each input. Upon capturing a signal, the scope stores as many samples as possible in its memory to represent the waveform.

Used in testing signal voltages in electronic devices such as radio broadcasting equipment, televisions and audio recording equipment, a digital storage oscilloscope offers the advantage of capturing and logging electronic events that occurred when no one was watching or which were otherwise impossible to determine.

Not to be confused with a voltmeter, a digital storage oscilloscope displays graphical representations of signal, enabling a more intuitive visual diagnosis of the unexpected voltage’s source. A voltmeter, on the other hand, records only the presence of unexpected voltage, requiring further troubleshooting and diagnostics. A DSO can measure the same voltage and show oscillation in the affected circuit. Digital storage oscilloscopes also offer visual display of the precise timing or shape of the pulse.

Acting as a simple signal tracer, a digital storage oscilloscope enables technicians to probe electronic device’s individual connections and components, to determine the malfunctioning part. In measuring the functions of the individual component of the device, the DSO locates where an expected signal is incorrect or absent. The DSO can also measure the components’ minor variations in operations and alert the technician of the need for fine tuning or replacement. To prevent erroneous replacement of parts, the DSO also helps technicians identify the parts that are still working.