First, the lens analysis The protective cover is also one of the most commonly used devices in the monitoring system and is mainly divided into indoor and outdoor. The main difference between the indoor protective cover is the size, the appearance is beautiful, and whether the surface treatment is qualified. The function is mainly dust and vandalism. The outdoor protective cover must have good sealing performance to ensure that rain cannot enter the protective cover to erode the camera. Some outdoor enclosures also have exhaust fans, heating plates, and wipers to better protect the equipment. When the weather is too hot, the exhaust fan works automatically; when it is too cold, the heating plate automatically works; when there is rain on the protective cover glass, the wiper can be activated through the control system. When selecting the protective cover, look at the overall structure. The smaller the number of mounting holes is, the better it is for waterproofing. Then look at whether the internal wiring is easy to connect. Finally, consider the appearance, weight, and mounting base. All the way to the video signal corresponds to a monitor or video recorder. If you want to send the images of one camera to multiple managers, you have better choose the video distributor. Because the attenuation of the parallel video signal is large, the impedance of the parallel video signal is not matched, the image is seriously distorted, and the line is unstable. In addition to impedance matching, the video distributor also has video gain so that the video signal can be sent to multiple output devices at the same time without being affected. 7 Video Switchers Multiple video signals need to be sent to the same place for monitoring. Each video can be assigned to a monitor. However, the monitor occupies a large area and the price is expensive. If you do not require monitoring at any time, you can add a switcher to the surveillance room and put the camera. The output signal is connected to the input of the switch. The output of the switch is connected to the monitor. The input of the switch is divided into 2, 4, 6, 8, 12, and 16, and the output is divided into single and dual channels. You can also switch audio simultaneously (depending on the model). The switcher has manual switching and automatic switching. The manual method is to see which way to switch the switch; the automatic method is to make the preset video delay switch in order, the switching time can be adjusted by a knob. Usually between 1 second and 35 seconds. The switcher is cheap (usually only three or five hundred dollars), the connection is simple, and the operation is convenient, but only one of the images in the input can be seen in one time period. To view multiple camera images on a monitor at the same time, you need to use a picture splitter. The screen divider has four divisions, nine divisions, and sixteen divisions. It can display the images of 4, 9 and 16 cameras simultaneously on one monitor, and can also be sent to the recorder for recording. Quadrisection is one of the most commonly used devices, and its performance and price ratio are also better. The quality and continuity of the image can meet most of the requirements. Nine and sixteen segments are more expensive, and the resolution and continuity of each image after segmentation are reduced, and the video is not good. There are also six-, eight-, and quad-segment devices, but image ratios, sharpness, and continuity are not ideal, and market usage is even smaller. Most of the splitters can display single images in addition to the images at the same time, can superimpose time and characters, set automatic switching, and connect alarm equipment. The most commonly used recording devices in surveillance systems are civilian video recorders and long-delay video recorders, which are easy to learn and video tapes are easy to store and purchase. Unlike home video recorders, time-lapse video recorders can work for a long time, can record images for 24 hours (using ordinary vhs video tapes) and even hundreds of hours, can be connected to alarm equipment, and automatically start recording when alarm signals are received. Time and date can be superimposed. Video recorder automatic recording program, select the video speed, video tape is automatically stopped after the end or rewind recording ... ... Although the outstanding performance of the time delay recorder, but expensive, and the current resolution is not very high, time-lapse video When the image will be lost part of the playback of the image is a meal of a jump in three, the choice of digital hard disk recorders can now be said to enter the digital monitoring host Spring and Autumn Period. Objectively speaking, because of the rapid development of computer technology, digital products have outstanding performance in hard disk video recording, network interaction, video alarm, work schedules, multi-screen display, etc., and have won the favor of many people in security. Surveillance, teller monitoring, civil monitoring and other fields gradually occupy a place. Because the development of this field is too fast, no national or industry standards have been issued so far. This article introduces some considerations and techniques in the selection and evaluation of digital products, and hopes to help you choose a digital monitoring host. THOR Series 1.0 Tons Electric Forklift Big Forklift,Used Electric Forklift,1.0 Tons Electric Forklift,High Quality 1.0 Tons Electric Forklift MASCOT ENTERPRISE LTD , https://www.green-mascot.com
1. Type of lens (categorized according to application)
Wide-angle lens: The angle of view is more than 90 degrees, and the image is deformed when the observation range is large.
Standard lens: The angle of view is about 30 degrees, and the range of use is wider.
Telephoto lens: within 20 degrees of viewing angle, the focal length can reach tens of millimeters or hundreds of millimeters.
Zoom Lens: The focal length of the lens is continuously variable, and the focal length can be changed from wide-angle to telephoto. The longer the focal length, the larger the image.
Pinhole lenses: Used for concealed observations, often mounted in places such as ceilings or walls.
2. The relationship between the size, distance, and focal length of the subject is assumed to be the width and height of the subject being wh, the distance between the subject and the lens being l, and the focal length of the lens being f.
3. Relative aperture In order to control the amount of light passing through the lens, an aperture is provided at the rear of the lens. Assuming that the effective aperture of the aperture is d, due to the relationship of light refraction, the effective effective aperture of the mirror light is d, which is greater than d, and the ratio of d to the focal length f is defined as the relative aperture a, that is, a=d/f, the relative of the lens The aperture determines the illuminance of the captured image, and the illuminance of the image and the inverse of the relative aperture of the lens represent the aperture of the lens. The smaller the f-number, the larger the aperture, and the greater the luminous flux reaching the ccd chip. Therefore, in the case of the same focal length f, the smaller the value of f, the better the lens.
4. The focal length of the lens 1) fixed focal length: the focal length is fixed, can be divided into two kinds of aperture and no aperture.
Aperture: The lens aperture can be adjusted in size. According to changes in the environment, the aperture should be adjusted accordingly. The size of the aperture can be adjusted manually or automatically. Manually adjusting the aperture is called a manual aperture. The lens comes with a micro motor that automatically adjusts the aperture, called the auto iris.
No aperture: fixed aperture, the amount of light is fixed. It is mainly used when the light source is constant or the camera comes with an electronic shutter.
2) Zoom: The focal length can be adjusted as needed to make the image of the subject zoom in or out. The commonly used zoom lens is a six-fold, ten-sale zoom.
Three Variable and Two Variable Lens Three Variable Lenses: Adjustable Focus, Focus, and Adjustable Focus.
Two variable lenses: adjustable focus, focus, auto iris.
5. First, with the lens principle In order to obtain the desired camera effect, in the matching lens, should pay attention to six basic elements:
a) Size of the subject b) Detail size of the subject c) Object distance d) Focal length e) Size of the CCD camera target surface f) Resolution of the lens and camera system Operation steps:
* Remove the lens tip and connect the lens.
* If using a cs lens, lower c circle (5mm) and lock the cs lens assembly.
* The c lens can be installed directly.
* Connect the video output (bnc) to a monitor or other device.
* Plug in the dc12v power supply/ac220v * Check that the led is on.
* When the image is blurred, adjust the lens focal length.
Second, the monitoring system equipment introduction 1 PTZ in the previous introduction, we often mentioned the PTZ, but some people do not have any perceptual knowledge of it, in fact, the PTZ is the installation platform consisting of two alternating currents, can horizontal and vertical movement . The pan/tilt we are talking about is different from the pan/tilt in the camera. The pan/tilt of the camera is generally only a tripod and can only adjust the position by hand. The pan/tilt system in the monitoring system is controlled by the remote system. Can control its direction of rotation. PTZ has many types: According to the use of the environment is divided into indoor and outdoor type, the main difference is that the outdoor type sealing performance is good, waterproof, dustproof, large load. According to the installation method, it is divided into side loading and lifting, that is, whether the pan/tilt is installed on the ceiling or on the wall. According to the appearance, it is divided into ordinary type and ball type. The ball type PTZ is placed in a hemispherical and spherical protective cover. In addition to preventing dust from disturbing the image, it is also concealed, beautiful and fast. When selecting the PTZ, consider the installation environment, installation method, working voltage, and load size, and also consider whether the performance price ratio and appearance are beautiful.
2 Brackets If the camera does not need to be rotated to monitor only a certain position, only the camera bracket can be used to meet the requirements. Ordinary camera brackets are simple to install, inexpensive, and varied. Ordinary brackets are short, long, straight, and bent, and different models are selected according to different requirements. The outdoor support mainly considers whether the load capacity meets the requirements, and then there is the installation position, because in practice we have found that many outdoor cameras are installed in special locations, some are installed on poles, some stand on tower cranes, and some are installed on iron. On the shelf... Due to various reasons, existing brackets may be difficult to meet requirements and require additional processing or improvement, and no more will be said here.
3 protective cover
4 The monitor monitor is the standard output of the monitoring system. With the monitor we can view the images sent from the front end. The monitor is divided into color, black and white, size 9,10,12,14,15,17,21 inches, etc., commonly used is 14 inches. The monitor also has a resolution and is represented by the same number of lines as the camera. In practice, it is generally required that the number of monitor lines matches the camera. In addition, some monitors have audio input, s-video input, rgb component input, etc. Except for the audio input monitoring system, most of the other functions are used for image processing work, and are not described here.
5 Video amplifier When the video transmission distance is relatively long, it is better to use a video line with a thicker wire diameter, and at the same time, the video amplifier can be increased in the line to enhance the signal strength to achieve long-distance transmission. Video amplifiers can enhance the video's brightness, chroma, and synchronization signals, but intra-line interference signals can also be amplified. In addition, too many video amplifiers cannot be cascaded in the loop, otherwise saturation will occur, leading to image distortion.
6 video distributor
8 screen divider
9 recorder
1, the choice of view interface Most digital monitoring host chose the IPC chassis as a shell, the appearance of the work to print and print should be exquisite and beautiful, the floppy drive and power switch with a mechanical lock to lock what kind of style to reduce human failure to help. If you can open the cover, you should pay attention to what fan and power supply you are using. For example, the dedicated fan on Pentium IIicpu has an average time between failures of more than 3 years, and the average time of failure of a typical fan may not be accurate. The digital monitoring host, which is continuously turned on, is a hidden trouble. In addition, it is convenient to watch the interface connection mode of the rear row.
In order to facilitate the operation, the interface should be finished, and the main functions can be reflected on the main interface at a glance. It is recommended to select an interface that looks professional and very intuitive. It is best to operate menus like windows.
Strong function expansion, the main functions are divided into monitoring functions, video functions, alarm functions, control functions, network functions, identity recognition functions, work schedule functions, if you can have a matrix, the best duplex talk, a lot of these two points Difficult to do. Here's an introduction.
2. Diversification of functions (1). Surveillance function The surveillance function is one of the main functions of the matrix host and the digitizing host. The monitoring function is nothing more than watching the scene and seeing the scene. If necessary, there should be a voice. Synchronize. The monitor effect is determined mainly by the sharpness, the real-time level of the screen, and the display form, which is different from the television display. The effect of different video card and capture card observation is not the same. Like measuring the clarity of a ccd camera, it is recommended to use a professional graphics test card and a camera with a high number of lines as the object of observation, to accurately read the horizontal and vertical resolution that can be observed, as the basis for monitoring the resolution, and generally the image per second. More than 17 frames appear to be more real-time images to the naked eye, and the teller system and some special surveillance sites require 25 frames per second or more. Usually, you can do some quick hand movements to observe this function, such as fast numbers. Numbers, claps, etc. This effect should be recorded as a playback record of the recording. The display format is generally 1, 4, 7, 9, 10, 16 and other screens, and the screen can also be cut to full screen. Each channel's brightness, contrast, color, saturation, and other parameters should be continuously adjustable. Otherwise, the multi-picture cannot be well viewed due to uneven light. This is also where the digital host is superior to the ordinary picture divider. When viewed in full screen, it can accurately reflect image quality, video speed, and graphics quality.
(2) Video:
The video effect is the core and vitality of the digital host. When you look at the real-time and clear images on the monitor, the playback effect recorded is not necessarily good. The most important effect of the forensics is to watch the video effects. In general, the video effect is better than the monitoring. The effect is more important.
Sharpness and real-time visibility and monitoring are similar. The memory used for the unit time recording and the single frame memory are also the most important parameters reflecting the video effect. The memory occupied by unit time recording and the space occupied by a single frame have a decisive influence on how long the same hard disk can be recorded and the rate at which images are transmitted on the Internet. General standard mpeg format, each channel to record to 600m per hour, while the mjpeg format records 16 pictures at the same time in the standard case accounted for 150m, the space difference is quite large, for the static picture, how much memory depends on the picture size image compression ratio ( Picture quality) and graphics format. How much memory for the dynamic picture depends on the image size of the image compression ratio, image format and whether the picture changes and the speed of change, the author once tested on a digital host, the use of mjpeg format, the image size is 800 × 600, the image movement accounted for 3k Byte, which occupies 180 bytes without motion. In addition, some hosts for security monitoring should have a preset alarm recording function, which can filter out information that has nothing to do with the alarm, and can greatly reduce the requirements for storage capacity. Some hosts also have the ability to automatically increase the number of recording frames after an alarm. This is also helpful for the storage of effective information.
A special reminder is that the same images look similar in quality, and the space they occupy may vary greatly (70m-550m/road/hour). At this time you can not see the machine monitoring interface display, only to return to the operating system (such as windows, nt, unix ...) to view the size of the file is accurate.
(3) Alarm function:
The alarm function mainly refers to the input alarm of the detector and the alarm of the image video frame measurement. After the alarm, the system will automatically open the recording function, and turn on the corresponding spotlight, alarm signal and network output signal through the alarm output function.
Image video frame detection alarm is a unique function of digital surveillance. He can easily set the video trigger area and sensitivity, in a certain sense can play a role of the detector.
According to the time period, automatic cloth does not have the function.
The output time of the alarm signal should be adjustable, and various alarm results should be clearly recorded in the computer.
(4) Control function:
Mainly refers to the camera through the host for the full range of camera PTZ, lens control, which is generally completed through a dedicated decoder, mainly to observe whether the operation is flexible *.
(5) Network function:
Through dial-up LAN access through a simple identification of the host can carry out a variety of monitoring and video control operations IV. Introduction to ultra-low illumination camera and infrared light
The ultra-low illumination camera is a hot product in the surveillance industry that has been introduced in recent years with the development of semiconductor technology. At present, it has been widely used in financial, cultural, hotel, office buildings, residential property management and other fields. Due to the difficulty of meeting the requirements of 24-hour continuous monitoring (because it is not possible to turn on the lights 24 hours at any location), the new type of ultra-illuminance cameras quickly developed this opportunity.
Most of the ultra-low-illuminance cameras use the “explicit had†technology, and the cameras with the “examination had ccd†will greatly increase the sensitivity to external light. In the near-infrared region, the sensitivity can be increased to 4 times that of ordinary cameras, such as (Figure 1). . Therefore, even in a very dark environment, this type of camera can usually see objects that are invisible to the human eye. The emergence of this technology has been welcomed by the surveillance market, and it can exhibit the best results under various lighting conditions. In particular, with dedicated infrared lighting equipment, high-resolution black-and-white images can be obtained, and monitoring of zero illuminance can be achieved (in the complete absence of light). In the near-infrared region of near-infrared range of 760mm-1100mm, clear black-and-white images can be achieved with infrared illumination at a suitable wavelength.
Similarly, a method for obtaining a low-light image is to increase the amount of light ccd in a single frame of image by a single-charge accumulation of charges, thereby improving the sensitivity of the camera to single-frame images. This method can also obtain lower illuminance index, but it needs to reduce the degree of coherence of the image. Therefore, when selecting this type of camera, it is necessary to pay attention not to use it together with the cradle as much as possible. Otherwise, the screen may be lost. There are other ways to obtain images with low illumination, but none of them can fundamentally solve the problem of illumination.
In addition, there are several points to note when choosing a low-light camera and infrared light.
First, you must choose the appropriate lens. In order to increase the sensitivity of the camera to the infrared light and the scene, a lens with a large amount of light should be used as much as possible, and attention should be paid to driving the drive level value of the large aperture as much as possible when using the auto iris or the electric two variable lens. Because generally with the lens focal length increases, the amount of light will be relatively reduced, in the selection of infrared lights to leave a certain margin, and pay attention to the infrared light indicators.
Second, the optional power supply for infrared lamps should meet the minimum electric power required by them as much as possible, and often the irradiation distance is not enough.
Third, to consider the degree of reflection of the scene being photographed, since infrared rays have the same characteristics as visible light such as reflection and refraction, therefore, if there is no good reflective environment (such as buildings, walls, signs) around the target scene, it should be considered The distance margin is 5. PTZ PTZ is a support device for the installation and fixation of cameras. It is divided into fixed and electric PTZ.
The fixed pan/tilt is suitable for the case where the scope of monitoring is not large. After the camera is mounted on the fixed pan/tilt, the horizontal and tilt angles of the camera can be adjusted. After the best working posture is reached, the adjustment mechanism can be locked.
The electric gimbal is suitable for scanning and monitoring a large area, and it can expand the monitoring range of the camera. The high-speed attitude of the electric pan/tilt head is achieved by two electric motors. The electric motor receives the signal from the controller and accurately operates the positioning. Under the control of the signal, the camera on the pan/tilt can automatically scan the surveillance area, and can also track the surveillance object under the control of the watch center personnel.
PTZ can be divided into a horizontal pan-tilt head that can only rotate left and right, and an all-around pan-tilt head that can both rotate left and right and can also rotate up and down according to the characteristics of its rotation. In general, the horizontal rotation angle is 0° to 350° and the vertical rotation angle is +90°. The horizontal rotation speed of the constant-speed gimbal is generally 3° to 10°/s, and the vertical speed is about 4°/s. The horizontal rotation speed of the variable-speed pan/tilt head is generally between 0° and 32°/s, and the vertical rotation speed is between 0° and 16°/s. In some high-speed camera systems, the speed of the pan/tilt head is up to 480°/s and the vertical rotation speed is above 120°/s. VI. Features of the DVR:
The basic function of the DVR is to convert analog audio and video signals into mpeg digital signals stored on the hard disk (hdd) and provide functions corresponding to recording, playing, and managing programs.
Its outstanding characteristics are reflected in the following aspects
1. Digital high-fidelity storage that implements analog programs can record and store analog and audio and video programs that are widely distributed and personally collected in an advanced digital manner. Recording at one time and repeatedly playing multiple times will not reduce the quality.
2. The comprehensive input/output interface provides antenna/TV cable, av terminal, s terminal input interface and av terminal, s terminal output interface. It can record almost all TV programs and other player, camera output signals, and easily connect with other audio-visual equipment.
3. Various optional image recording levels For the same program source, three levels of image quality recording are provided: high, medium, and low. When the highest level is selected, the recorded image quality is close to the image quality of dvd.
4. Large-capacity long-term program storage, strong scalability Users can choose to use 20.4gb, 40gb or more hard drives for program storage. Calculated at 20.4gb capacity, the recordable program time at the selected code rate is shown in the following table:
Bit rate (mbps) Recordable show time (hours)
6 7
4 10
2 20
1.15 38
5. With advanced time shifting function When you have to interrupt watching TV programs, the user only needs to press the time shifting key. The programs starting from the interruption of the viewing time will be automatically saved. After the user finishes the transaction, The program continues to be viewed from where it left off without any pause.
6. Perfect appointment recording/playing program features. The user can freely set the start time, length of time, etc. for starting recording/playing the program. Through the editing combination of scheduled program listings, it is possible to systematically record a variety of intermittent television programs, including television series.
7. Powerful Network Information Home appliance center users can enjoy rich online information via a network communication interface, using a dvr-tailored web browser and equipped with corresponding network resources.
8. Providing a convenient method for managing recorded programs The user can organize and classify the recorded programs according to the recording time, the program type, etc., and freely set the bookmarks at the favorite places.
9. Provides arbitrary playback methods Due to the fast and random storage of the hard disk, when enjoying a recorded or recording program, you can perform trick-play with more, more flexible methods than the current DVD player. The image is smoother and has higher detail resolution when played slowly.
VII. Selection techniques of optical transceivers in security projects At present, there are many types of digital video optical transceivers on the market, and there are a wide range of technical indicators. Most of the engineering companies and users also lack the corresponding means to judge the rationality and authenticity of technical indicators. It's easy to get lost when choosing a product. This article describes two key technical indicators that are more critical and easy to verify in the project, and focuses on how to select multiple digital video optical transceivers in security monitoring engineering from the perspective of feasibility and practicality.
1. Technical Specifications Multi-channel digital video optical transceivers may have multiple functions. Each type of function has corresponding technical specifications, such as video indicators, audio indicators, asynchronous data indicators, Ethernet indicators, and so on. Specific technical indicators can require manufacturers to provide third-party test certificates. Conditional contractors should conduct retesting in accordance with manufacturer-supplied specifications before purchasing equipment to verify the actual technical specifications of the equipment and the integrity of the manufacturer. Here, the following two video indicators are briefly described from the engineering point of view.
1.1 3db video bandwidth is enough The video bandwidth is an old growing issue. With insufficient video bandwidth, the details of the monitor screen are not clear enough, the horizontal resolution is low, and even serious color distortion or loss occurs. It is because of the importance of video bandwidth to image quality that some unscrupulous manufacturers intentionally exaggerate the video bandwidth of the product to deceive customers. A multi-channel digital video optical transceiver produced by a manufacturer claims that its video bandwidth is 8m, and its externally announced video sampling frequency is 12.5m. In accordance with the Nyquist sampling law, to truly restore the signal, the sampling frequency should be at least twice the signal frequency. In this case, the theoretical video bandwidth of the optical transceiver of this manufacturer cannot exceed 6.25m in any case. Obviously, this is a lie that exaggerates the performance of deceiving customers, so that manufacturers with no commercial reputation should not be considered for inclusion in the scope of purchase. However, not all customers are able to accurately identify manufacturer's lies. For general contractors and users, the device's video bandwidth can be roughly judged by observing the details of the image.
1.2 apl range is wide enough
Apl, the average level of the image, many builders are not paying attention or are not familiar with this indicator. However, if we talk about a problem encountered in some projects: the video signal is transmitted through the optical transceiver, when the screen has a large area of ​​white (such as when the camera is illuminated by a strong light) the monitor will horizontally shake, then The engineering staff is no stranger to it. This is because the apl range of video optical transceivers produced by some manufacturers is too narrow. When there is a large area of ​​white in an image signal, the DC component in each image signal increases, apl will increase, and the amplitude of the horizontal synchronization signal will decrease. Or, the monitor cannot detect line synchronization and screen jitter occurs.
2. Considerable considerations As a security monitoring project, the feasibility of equipment should be the first consideration. The availability of equipment is a must for equipment manufacturers to consider when designing products. However, some manufacturers may not want to do or do not know how to do this work for some reasons. Here, the following issues are briefly discussed from the engineering perspective.
2.1 Convenient power supply, wide range of power supply is the primary consideration for ensuring the digital video optical transceiver reliability, power supply can not be guaranteed, reasonable, and the feasibility of digital video optical transceiver becomes a fishing month. It is more convenient to use 220 vac power video optical transceiver to obtain power, and the performance is higher. The 220 vac power optical transceiver should be selected as much as possible in the project. This type of optical transceiver currently has two main power supply methods. One is an external power supply type, and the other is a power supply internal type, that is, the power supply and the optical transceiver are integrated. From the perspective of engineering applications, the built-in power supply is not only easy to install, but also highly scalable. Therefore, the current multi-channel digital video optical transceivers mostly use built-in power supplies.
Based on the situation of the domestic power grid and combined with the actual site conditions, a multi-channel digital video optical transceiver with a wide input power range should be selected as much as possible. Generally, the optical transceiver using switching power supply should be selected as much as possible. Compared with the linear power supply, the switching power supply is not only highly efficient, but also has a wide input voltage of the switching power supply, which basically guarantees normal operation in the range of 160 VAC to 265 VAC, and its output voltage does not change with the input voltage, and thus does not affect the optical transceiver. Work performance and technical indicators will not cause the optical transceiver to start repeatedly due to instability of the power grid and interrupt the transmission of monitoring video and audio signals.
2.2 Strong adaptability of temperature and humidity In some security monitoring projects, the working conditions of the optical transceiver are rather poor, the temperature variation range is wide, and the air humidity is high. Occasionally, some field monitoring points will also lose power, and the optical transceivers will heat up when they work. When the power is turned off, there will be condensation beads when the equipment is cooled. All of these require multiple digital video transceivers to have more consideration in the temperature range and allowable humidity, so as to ensure that they can work stably in harsh environments and adapt to security monitoring needs.
3.1 Appearance and generosity, reasonable structure Multi-channel digital video optical transceiver High technical content, its appearance should be small and exquisite, beautiful and generous, the overall structure must meet the engineering installation requirements as much as possible. In addition to the general indoor multi-channel digital video optical transceivers, the 19-inch cabinet should also be considered as the π-barrier, and the need to place the optical transceiver on the desktop or wall should be taken into account. In addition, multi-channel digital video transceivers must also have good thermal performance and electrical contact performance.
3.2 Rich Interfaces and Reasonable Layout In addition to requiring adequate video interfaces, multi-channel digital video transceivers may require or be equipped with other feature-rich interfaces, such as high-fidelity audio interfaces, ordinary telephone interfaces, asynchronous data interfaces, and Ethernet interfaces. With the switch interface, etc., this requires that the selected multi-channel digital video optical transceiver must have the system upgrade capability, so that it will not completely replace the equipment due to network upgrade or system function change, thereby protecting the user's upfront investment.
There are many kinds of multi-channel digital video optical transceiver interfaces, and there are a large number of interfaces. There may be some modes to set the dial switch. The user interface formed by all these elements should be reasonably laid out, and there should be considerable space for operation between interfaces to facilitate the project. Installation and maintenance. For example, the video interface is too intensive, and in actual applications, an awkward situation in which a normal video connector must be removed to repair a certain video connector appears.
3.3 The meaning of the indicator light is clear, which facilitates the opening and maintenance of the project. To facilitate the opening of the project and the maintenance of the project, the multi-channel digital video optical transceiver shall be marked with a clearly defined indicator. In addition to the power indicator, multiple transceivers for digital video transceivers must have video presence or absence to indicate whether the corresponding video channel has input or output video signals. Engineering personnel and users are involved in the engineering startup phase and project maintenance phase. According to the indication of the video indicator, the situation during the opening and maintenance can be judged, the fault point can be located, and the possible problems can be solved as soon as possible.
In addition, for the audio and data sections, corresponding indicators should also be provided. The simple way is to refer to the telecommunication equipment's practice and provide the synchronization indicator and the loop indicator. According to this, the engineering personnel and the equipment manufacturer can judge whether the equipment system is faulty or the interface is partially faulty, so as to make a correct response.
For Ethernet interfaces, connection/activity indicators, full/half duplex indicators, and 10m/100m indicators should be provided in accordance with the general requirements for data communications equipment.
Multi-channel digital video transmitters should also provide system indicators to indicate whether the sending device is normal and whether the receiving device is normal. This is to make it easier for engineers to distinguish whether the device fault is an optical fiber link failure.
In summary, the user can consider the technical indicators, feasibility, and practicality of the equipment when selecting the equipment, compare the methods according to the above methods, and make appropriate plans according to the actual conditions of the project. Suitable for their own multi-channel digital video transmitter.