A digital storage oscilloscope (DSO) is an

oscilloscope An oscilloscope (formerly known as an oscillograph, informally scope or O-scope) is a type of electronic test instrument that graphically displays varying voltages of one or more signals as a function of time. Their main purpose is capturing i ...

which stores and analyses the input signal digitally rather than using

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...

techniques. It is now the most common type of oscilloscope in use because of the advanced trigger, storage, display and measurement features which it typically provides. The input analogue

signal A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In ...

sampled Sample or samples may refer to: * Sample (graphics), an intersection of a color channel and a pixel * Sample (material), a specimen or small quantity of something * Sample (signal), a digital discrete sample of a continuous analog signal * Sample ...

and then converted into a digital record of the amplitude of the signal at each sample time. The sampling frequency should be not less than the

Nyquist rate In signal processing, the Nyquist rate, named after Harry Nyquist, is a value equal to twice the highest frequency ( bandwidth) of a given function or signal. It has units of samples per unit time, conventionally expressed as samples per se ...

to avoid

aliasing In signal processing and related disciplines, aliasing is a phenomenon that a reconstructed signal from samples of the original signal contains low frequency components that are not present in the original one. This is caused when, in the ori ...

. These digital values are then turned back into an analogue signal for display on a

cathode ray tube A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a ...

(CRT), or transformed as needed for the various possible types of output—

liquid crystal display A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liq ...

chart recorder A chart recorder is an electromechanical device that records an electrical or mechanical input trend onto a piece of paper (the chart). Chart recorders may record several inputs using different color pens and may record onto strip charts or circu ...

plotter A plotter is a machine that produces vector graphics drawings. Plotters draw lines on paper using a pen, or in some applications, use a knife to cut a material like Polyvinyl chloride, vinyl or leather. In the latter case, they are sometimes k ...

or network interface. Digital storage oscilloscope costs vary widely; bench-top self-contained instruments (complete with displays) start at or even less, with high-performance models selling for tens of thousands of dollars. Small, pocket-size models, limited in function, may retail for as little as US$50.

Comparison with analog storage

The principal advantage over analog storage is that the stored traces are as bright, as sharply defined, and written as quickly as non-stored traces. Traces can be stored indefinitely or written out to some external data storage device and reloaded. This allows, for example, comparison of an acquired trace from a system under test with a standard trace acquired from a known-good system. Many models can display the waveform prior to the trigger signal. Digital oscilloscopes usually analyze waveforms and provide numerical values as well as visual displays. These values typically include

average In colloquial, ordinary language, an average is a single number or value that best represents a set of data. The type of average taken as most typically representative of a list of numbers is the arithmetic mean the sum of the numbers divided by ...

maxima and minima In mathematical analysis, the maximum and minimum of a function are, respectively, the greatest and least value taken by the function. Known generically as extremum, they may be defined either within a given range (the ''local'' or ''relative ...

root mean square In mathematics, the root mean square (abbrev. RMS, or rms) of a set of values is the square root of the set's mean square. Given a set x_i, its RMS is denoted as either x_\mathrm or \mathrm_x. The RMS is also known as the quadratic mean (denote ...

(RMS) and

frequencies Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

. They may be used to capture transient signals when operated in a single sweep mode, without the brightness and writing speed limitations of an analog storage oscilloscope. The displayed trace can be manipulated after acquisition; a portion of the display can be magnified to make fine detail more visible, or a long trace can be examined in a single display to identify areas of interest. Many instruments allow a stored trace to be annotated by the user. Most digital oscilloscopes use

flat-panel display A flat-panel display (FPD) is an electronic visual display, electronic display used to display device, display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment. Flat-panel disp ...

s similar to those made in high volumes for computers and television displays. Digital storage oscilloscopes may include interfaces such as a parallel printer port,

RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such as a compu ...

serial port,

IEEE-488 Glycoprotein Ib (GPIb), also known as CD42, is a component of the GPIb-V-IX complex on platelets. The GPIb-V-IX complex binds von Willebrand factor, allowing platelet adhesion and platelet plug formation at sites of vascular injury. Glycoprotein ...

bus,

USB Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

port, or

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

, allowing remote or automatic control and transfer of captured waveforms to external display or storage.

PC based

A personal computer-based digital oscilloscope relies on a PC for user interface and display. The "front end" circuits, consisting of input amplifiers and analog to digital converters, are packaged separately and communicate with the PC over USB, Ethernet, or other interfaces. In one format, the "front end" is assembled on a plug-in expansion card that plugs into the computer backplane. PC based oscilloscopes may be less costly than an equivalent self-contained instrument as they can use the memory, display and keyboard of the attached PC. Displays may be larger, and acquired data can be easily transferred to PC hosted application software such as spread sheets. However, the interface to the host PC may limit the maximum data rate for acquisition, and the host PC may produce sufficient electromagnetic noise to interfere with measurements.Alan S. Morris, Reza Langari ''Measurement and Instrumentation: Theory and Application'', Academic Press, 2011 page 180

References

External links

Digital Storage Oscilloscope Measurement Basics

* ttps://www.rohde-schwarz.com/applications/benefits-of-r-s-rto-digital-trigger-system-application-note_56280-15720.html Benefits of a Digital Trigger System {{Oscilloscopes Electronic test equipment Laboratory equipment Signal processing