Waveform monitor - AbsoluteAstronomy.com

A waveform monitor is a special type of oscilloscope

Oscilloscope

An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or 'Y' axis, plotted as a function of time,...

used in television production applications. It is typically used to measure and display the level, or voltage

Voltage

Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...

, of a video signal with respect to time

Time

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

.

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

Vertical blanking interval

The vertical blanking interval , also known as the vertical interval or VBLANK, is the time difference between the last line of one frame or field of a raster display, and the beginning of the first line of the next frame. It is present in analog television, VGA, DVI and other signals. During the...

of a video signal, as well as the colorburst

Colorburst

Colorburst is a analog video, composite video signal generated by a video-signal generator used to keep the chrominance subcarrier synchronized in a color television signal...

between each line of video.

Waveform monitors are used for the following purposes:

To assist with the calibration of professional video camera
Professional video camera
A professional video camera is a high-end device for creating electronic moving images...

s, and to "line up" multiple-camera setup
Multiple-camera setup
The multiple-camera setup, multiple-camera mode of production, or multicam is a method of filmmaking and video production. Several cameras—either film or professional video cameras—are employed on the set and simultaneously record or broadcast a scene...

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
Telecine
Telecine is transferring motion picture film into video and is performed in a color suite. The term is also used to refer to the equipment used in the post-production process....

(film-to-tape transfer), color correction
Color correction
Color correction by using color gels, or filters, is a process used in stage lighting, photography, television, cinematography and other disciplines, the intention of which is to alter the overall color of the light; typically the light color is measured on a scale known as color temperature, as...

, and other video production
Video production
Video production is videography, the process of capturing moving images on electronic media even streaming media. The term includes methods of production and post-production...

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
Television studio
A television studio is an installation in which a video productions take place, either for the recording of live television to video tape, or for the acquisition of raw footage for post-production. The design of a studio is similar to, and derived from, movie studios, with a few amendments for the...

, 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
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...

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

Vectorscope

A vectorscope is a special type of oscilloscope used in both audio and video applications. Whereas an oscilloscope or waveform monitor normally displays a plot of signal vs. time, a vectorscope displays an X-Y plot of two signals, which can reveal details about the relationship between these two...

. 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

Cathode ray tube

The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

. A sync stripper circuit was used to isolate the sync pulses and colorburst

Colorburst

Colorburst is a analog video, composite video signal generated by a video-signal generator used to keep the chrominance subcarrier synchronized in a color television signal...

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

Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

and digital signal processing

Digital signal processing

Digital signal processing is concerned with the representation of discrete time signals by a sequence of numbers or symbols and the processing of these signals. Digital signal processing and analog signal processing are subfields of signal processing...

, 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

Eye pattern

In telecommunication, an eye pattern, also known as an eye diagram, is an oscilloscope display in which a digital data signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep...

and jitter

Jitter

Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source. Jitter may be observed in characteristics such as the frequency of successive pulses, the signal amplitude, or phase of...

displays for measuring the physical layer

Physical layer

The physical layer or layer 1 is the first and lowest layer in the seven-layer OSI model of computer networking. The implementation of this layer is often termed PHY....

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

Ancillary data

Ancillary data , in the context of television systems, refers to a means which by non-video information may be embedded within the serial digital interface...

and television-related metadata

Metadata

The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...

such as timecode, closed captions and the v-chip

V-chip

V-chip is a generic term for technology used in television set receivers in the USA, Canada, and Brazil which allows the blocking of programs based on their ratings category. It is intended for use by parents to manage their children's television viewing...

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

Raster graphics

In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...

. They may come with a flat-panel liquid crystal display

Liquid crystal display

A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....

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

Manufacturers of waveform monitors

The following companies manufacture waveform monitors:

Blackmagic Design - http://www.blackmagic-design.com
Phabrix
Hamlet Video International
Compuvideo
Tektronix
Tektronix
Tektronix, Inc. is an American company best known for its test and measurement equipment such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. In November 2007, Tektronix became a subsidiary of Danaher Corporation....
Leader Instruments Corp
Videotek, a subsidiary of Harris
Harris Corporation
Harris Corporation is a Florida-based international communications equipment company that produces wireless equipment, electronic systems, and both terrestrial and spaceborne antennas for use in the government, defense, and commercial sectors. It is also the largest private-sector employer in...
DK-Technologies
Used Waveform Monitors
Magni Systems
OmniTek
Serious Magic DV Rack--a waveform monitor that runs on a laptop.
TRANSVIDEO
Astrodesign
SWIT Electronics

Manufacturers of waveform monitors

See also