Photonics Dictionary: T

To transform a picture or image field into a television signal for transmission.

The term that represents the size of one of the many small elements into which a television image is necessarily broken down for transmission.

The span of frequencies within which a single channel of broadcast television must fall; in the US, it is 6 MHz.

A camera containing an electronic image sensor that converts the image to an electronic signal suitable for television applications.

The value equal to the raster height divided by the half-period of a periodic test pattern.

A device designed to enlarge the image of a microscopic object by television process. It may be a flying spot scanner that is used to scan the microscope slide, or a camera tube-microscope...

A television receiver that receives the signals generated by a television camera directly, or remotely through a radio signal. It may be used to continuously check image and sound reception; as a...

A television display system in which the television signal is converted to an image that is projected onto either a front or rear projection screen.

The combination of the audio and visual signals that are transmitted and received at the same time, correlating the scene and sound in a television picture.

An electronic device used to encode video and audio signals of a television camera into radio waves that are broadcast to remote receivers. The video and audio components are transmitted...

The graph of the oscillating variations composing the wave of a video signal.

The process or device by which more than one signal can be sent over a single channel by using different time intervals for the different signals. This may be done by varying the pulse duration,...

The law stating that the brightness of an object that is examined through a slotted disc, rotating over a critical frequency, is proportional to the angular aperture divided by the opaque sectors.

In optics, a shape often given to the leading edge of a projectile. In any side view it appears as a pointed arc, while any cross section perpendicular to its long axis appears as a circle.

A device for extracting a portion of the optical signal from a fiber.

A waveguide having a characteristic that is altered continuously with the distance traveled, relative to the axis of its path.

1. The anode or anticathode of an x-ray tube that emits x-rays when bombarded by electrons. 2. The screen in a television imaging tube that is scanned by an electron beam to determine the...

In television, a lateral displacement of the lines from their normal position due to the instability of a synchronizing circuit. Visually, it appears as though parts of the images had been torn away.

1. The term used to describe any of the many instruments used to remotely record physical dimensions, such as strain, temperature or pressure, and transmit this data to a receiving station. 2. A...

The ratio between the focal length of a lens having a longer focal length than that of the standard lens used with a camera, and the focal length of the standard lens. It is used to provide an...

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

The use of head-mounted displays and body-operated remote actuators to control distant machinery. Provides a virtual environment for humans to control devices, robots, etc., in a hostile real...

An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant objects more distinct, by enlarging their images on the retina.

The image of the aperture stop, usually the objective lens, that is produced by the eye lens. When the exit pupil of the telescope coincides with the entrance pupil of the eye of the observer, the...

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

A coating having pigments that change color when exposed to heat. This effect has been widely used to monitor hot spots in mechanical parts.

A characteristic of laser output, calculated by dividing the speed of light by the linewidth of the laser beam. The temporal coherence length of different lasers thus varies from a few centimeters to...

Characteristic of deflected light power defined as the quadratic invariant function of the video signal amplitude.

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

An optical matrix that does not require perfection in both states of the crosspoint, so that all the optical switches can be tap-off devices in which a fraction of the optical energy is transferred...

The process of attaching a device to the end of a fiber cable to enable the beam to be transmitted farther, to pass to another device and to avoid reflection.

A device used to detect elevation, pyramid and resolution errors in prisms and other components by bringing them into contact with the three highly polished, flat, perpendicular surfaces that form...

The section of crystal symmetry having only one-quarter of the greatest number of faces permitted by the crystal system of which the section is a member.

With respect to crystals, having three mutually rectangular axes, only two of which are equal.

A precise telescope set on a pair of rotation axes, the horizontal and vertical axes equipped with two divided circles. One circle measures horizontal angles and the other measures vertical angles....

The process of producing a visible two-dimensional image of a scene that is dependent on differences in thermal or infrared radiation from the scene reaching the aperture of the imaging device.