A waveform monitor is a special type of

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 ...

used in

television production A television show, TV program (), or simply a TV show, is the general reference to any content produced for viewing on a television set that is broadcast via over-the-air, satellite, and cable, or distributed digitally on streaming plat ...

applications. It is typically used to measure and display the level, or

voltage Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...

, of a video signal with respect to

time Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...

. The level of a video signal usually corresponds to the brightness, or

luminance Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls wit ...

, of the part of the image being drawn onto a regular video screen at the same point in time. A waveform monitor can be used to display the overall brightness of a television picture, or it can zoom in to show one or two individual lines of the video signal. It can also be used to visualize and observe special signals in the vertical blanking interval of a video signal, as well as the colorburst between each line of video. Waveform monitors are used for the following purposes: * To assist with the calibration of professional video cameras, and to "line up"

multiple-camera setup The multiple-camera setup, multiple-camera mode of production, multi-camera or simply multicam is a method of filmmaking, television production and video production. Several cameras—either film cameras, film or professional video cameras—are ...

s being used at the same location in order to ensure that the same scene shot under the same conditions will produce the same results. * As a tool to assist in telecine (film-to-tape transfer), color correction, and other

video production Video production is the process of producing video content. It is the equivalent of filmmaking, but with video recorded either as analog signals on videotape, digitally in video tape or as computer files stored on optical discs, hard drives, SSDs, ...

activities * To monitor video signals to make sure that neither the color gamut, nor the analog transmission limits, are violated. * To diagnose and troubleshoot a

television studio A television studio, also called a television production studio, is an installation room in which video productions take place, either for the production of live television and its recording onto video tape or other media such as SSDs, or for ...

, or the equipment located therein. * To assist with installation of equipment into a television facility, or with the commissioning or certification of a facility. * In manufacturing test and

research and development Research and development (R&D or R+D), known in some countries as OKB, experiment and design, is the set of innovative activities undertaken by corporations or governments in developing new services or products. R&D constitutes the first stage ...

applications. * For setting camera exposure in the case of video and digital cinema cameras. A waveform monitor is often used in conjunction with a vectorscope. Originally, these were separate devices; however modern waveform monitors include vectorscope functionality as a separate mode. (The combined device is simply called a "waveform monitor"). Originally, waveform monitors were entirely analog devices; the incoming (analog) video signal was filtered and amplified, and the resulting voltage was used to drive the vertical axis of 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 ...

. A sync stripper circuit was used to isolate the sync pulses and colorburst from the video signal; the recovered sync information was fed to a sweep circuit which drove the horizontal axis. Early waveform monitors differed little from oscilloscopes, except for the specialized video trigger circuitry. Waveform monitors also permit the use of external reference; in this mode the sync and burst signals are taken from a separate input (thus allowing all devices in a facility to be genlocked, or synchronized to the same timing source). With the advent of

digital television Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...

and

digital signal processing Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are a ...

, the waveform monitor acquired many new features and capabilities. Modern waveform monitors contain many additional modes of operation, including ''picture mode'' (where the video picture is simply presented on the screen, much like a television), various modes optimized for color gamut checking, support for the audio portion of a television program (either embedded with the video, or on separate inputs), eye pattern and

jitter In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a signifi ...

displays for measuring the

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechani ...

parameters of serial-digital television formats, modes for examining the serial digital protocol layer, and support for ancillary data and television-related

metadata Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive ...

such as timecode, closed captions and the v-chip rating systems. Modern waveform monitors and other oscilloscopes have largely abandoned old-style CRT technology as well. All new waveform monitors are based on a ''rasterizer'', a piece of graphics hardware that duplicates the behavior of a CRT vector display, generating a raster signal. They may come with a flat-panel

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 ...

, or they may be sold without a display, in which case the user can connect any VGA display.

See also