Components of a fiber optic CCTV transmission system
The only goal of the fiber optic link in a fiber optic transmission system is CCTV Transmission of electrical signals at a distance between any two points A and B, without Reducing the quality of the transmitted signal. In this way, the fiber connection transparent to the user. A similar situation is with a phone call where you want be able to another person, anywhere, they speak as if standing next to you.
The basic elements of a system for transmitting CCTV fiber optic as follows:
• Electronics optic converter (transmitter) at the end of the camera connection.
This camera takes the analog signal of 1 V peak to peak of the surveillance camera and transforms into a light that varies in proportion to the camera output Signal. The signal of the light generated by an LED (Light Emitting Diode) or laser Transmitter, which is designed to couple a maximum of light produced in a fiber.
• fiber light transmission and optical fiber cable.
The optical fiber guides light from the LED or laser transmitter with a minimum the loss of the screen or end controller connection matrix. The optical fiber itself is protected by a variety of sheath materials with a cable design to appropriate for the specific application. The fiber optic cable is connected to terminal In units for mounting screw or bayonet.
• Optical Electric Converter (receiver) at the end to monitor the connection.
This device takes the signal from the optical fiber and converts it into a analog electrical signals, which is consistent with the requirements to control the seizure. The light in the power conversion is performed by a semiconductor detector is made called a photodiode or an avalanche photodiode. subsequent electronics regenerates the output signal. Products of higher quality producer to offset losses and fiber optic intensity variation with Transmitter Output
Time and temperature by automatic gain control, a standard type 1 v Peak to peak output format that the output of the camera produces.
• Control data and audio connections.
Cameras in CCTV systems are either fixed, watching a particular scene or laptop so that the different scenes are displayed under the direction of the operator, as would to place in the remote area. In the case of fixed cameras and fiber optics Link is necessary to monitor only transmit video information from the camera, requires only a single optical fiber link for each camera to follow its trajectory. In the case of move the camera are then a return signal to be supplied by the control room of the device is usually a second optical fiber. It is customary Links for this return of control for remote control of camera PTZ – Pan, Tilt and Zoom functions provide more Camera Cases and washing activation.
When control of the camera is then of the fiber optic link interface electronics must be used compatible with the protocols used by the controller manufacturer. These functions are transmitted through the fiber optic link back with a digital transmission standard Format such as RS232, RS485/422, 20mA loop current, and, more recently Echelon
FTT10A Lonworks. In addition, some manufacturers require a controller data return Canal to confirm the movement of the camera camera. This return is generally encoded data from the optical transmitter and electronic equipment sent to the same fiber the video signal.
Help Point facilities and access control requires the transfer of two audio channels Signals on the fiber connection. Also optical transmitter and receiver are available This facility, in addition to video and control data includes links to all
the same two fibers. It is also possible that all these video, audio and data The transfer functions on a fiber with different wavelengths (color) lights Sources to transmit light in any direction. This technique is known as the wavelength Division Multiplexing, it maximizes the use of fiber cores installed at the expense transmitters and receivers more expensive.