Glossary

Impedance

Is the input and output characteristic of any electrical system and is measured in ohms. For maximum signal transfer, the input and out- put impedance should be the same. CCTV systems have a 75 ohm impedance.

Incandescent Light

Is a type of artificial light source invented by Thomas Edison in 1862. It has a good spectral response but low life and efficiency.

Index of Refraction

Is a ratio between the angle of incidence to the angle of refraction of light. It depends upon the density of a medium. A denser medium will have a higher index of refraction and will also bend the light more.

Infrared Detector

Can be used in conjunction with a CCTV system to switch the relev- ent camera on to the monitor in event of an activation.

Infrared Link

Transmission medium in which video, data or audio are modulated with infrared light and then transmitted via free space to a receiver in a remote location.

Infrared Radiation

Is electromagnetic radiation with a wavelength of more than 750 na- nometers. It is not visible to the human eye.

Interference

Is external energy which interferes with an electrical signal causing picture distortions.

Interlacing

Is the process of combining even and odd fields to form a frame.

Interline Transfer Chip

Is a type of chip used in most of the current CCTV cameras as the charge read out method is more efficient than a frame transfer CCD chip. Vertical streaking and small pixel size are some of the short- comings.

Iris

Junction box

Empty box (mostly weatherproof) to be mounted close to the elec- tronic device. Simplifies cabling and may contain a twisted pair transmitter, PSU etc.

LAN

Local Area Network connects different computers so that they can communicate with each other. Different connection protocols are possible.

LD

Laser diode is a type of light source which generates a single fre- quency in the high end of the infrared spectrum and has a band- width of 1000 MHz. It is used in fibre optics and infrared links.

LED

Light Emitting Diode is a type of light source which generates an infrared frequency when stimulated by electricity. It is used in fibre optics, infrared links and as an infrared light source for monochrome cameras.

Lens Calculator

Is a calculator provided by many lens manufacturers to help calculate the focal length of the lens that will provide the required image.

Lens Hunting

Is a problem where the iris is continually opening and closing. Using the ALC adjustment in the lens, this should rectify the problem.

Lens Mount

See C-mount or CS-mount.

Light

Is electromagnetic radiation between 400 nm and 750 nm which is detectable by the human eye.

Light Sensor (photocell)

Is a device which is activated by a present amount of light falling on it. It can be used to switch infrared illuminators On/Off.

Limit Switch

Is a device placed inside or outside the Pan Tilt head and used to limit the angles of pan and tilt.

The part of a lens that can be adjusted to vary the amount of light passing through the lens and falling on the CCD chip.

Line

16

Iris Plug

Push in connector which connects the camera to an auto iris lens to provide power to the iris motor and to send the video signal which controls the iris opening.

ISDN

Integrated Services Digital Network is a type of telephone network which is used to connect networks remotely.

Joystick Controller

Is a control device in the form of a stick in a PTZ controller used to con- trol the pan, tilt and zoom movement of a pan tilt head or dome.

Is the basic unit of a frame or field containing the charge which is pro- portional to the light falling at various points on the scanning line.

Looping Switcher

Is a type of switcher with looping outputs. These outputs allow the camera to be connected to another device without affecting the usage of the switcher.

Lumen

Is a measurement of light which indicates the amount of light radi- ated by a one candela light source.

Luminance Signal

Is that part of the video signal which contains the information on the brightness of the picture.

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Siemens TFT, CRT manual Lan

CRT, TFT specifications

Siemens, a prominent name in electronics and engineering, has made significant contributions to display technology, particularly in the realms of Thin Film Transistor (TFT) and Cathode Ray Tube (CRT) displays. These technologies have paved the way for advancements in visual media, ranging from television sets to computer monitors.

TFT display technology, a type of LCD (Liquid Crystal Display), employs thin film transistors to produce brighter and more vibrant images. One of the main features of TFT displays is their ability to deliver high resolution and excellent color reproduction, making them ideal for various applications such as smartphones, tablets, and laptops. TFT screens utilize an active matrix approach, which allows each pixel to be controlled individually. This method results in faster response times and improved image quality, with less motion blur, compared to older passive matrix displays.

One of the key characteristics of TFT technology is its versatility in different settings. It supports a wide range of viewing angles, which enhances the user experience whether one is viewing the display head-on or at an angle. Additionally, TFT displays are known for their thin profile and lightweight design, contributing to the overall portability of devices that incorporate them.

On the other hand, CRT technology, which was once the standard for televisions and computer monitors, uses electron beams and phosphorescent screens to produce images. One of the defining features of CRTs is their ability to display deep blacks and a wide color gamut. CRT technology can achieve high refresh rates, reducing flicker and improving the quality of fast-paced visuals. However, CRTs tend to be bulkier and heavier than modern display technologies like TFT.

Despite the evolution towards flat-panel displays, CRT technology is still appreciated for its natural color and motion portrayal. Siemens has leveraged these characteristics to produce quality CRT monitors that were favored in professional settings, including graphic design and medical imaging, where color accuracy is paramount.

In summary, Siemens has played a vital role in advancing both TFT and CRT technologies. TFT displays are recognized for their high resolution, fast response times, and design versatility, while CRTs are celebrated for their rich color and depth. As technology continues to advance, the legacy of these display types remains influential in shaping modern electronic devices.