One Should Grasp the Main Video Signal Transmission

Video Signal Transmission

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Wireless-camera or Cable camera connections are two of the most used means for transmission to the viewer of the images that are captured by the Surveillance Camera. Before selecting anyone of them, one should grasp the main Video Signal.

The video signal
one area of video is being created by the Convention and sweep exactly 312 1/2 times and this reproduced on the monitor. A second scan of 312 lines 2.1 is accurately half a line down and interlaced with the first cycle to form an image of 625 lines. This is called a 2:1 interlaced image. Line 625 is known as a video frame consists of two interlace fields. Stress is a tension in the bottom of the sync pulse above the target, resulting in a peak to peak (p/p). The luminance (brightness) component of the signal is 0.3 volts to one volt, is 0.7 volts maximum. This is known as a composite video signal, since the timing information and video are combined into a single signal.

Synchronizing
the video signal from a TV camera has to provide a variety of information at the monitor for a correct TV picture to be displayed. This information can be divided into: Synchronizing pulses to tell the monitor when to start a line and a frame; video information that tells the monitor how bright a exacting point in the picture should be; chrominance that tells the monitor what colors a particular part of the picture should be (color cameras only).

Bandwidth

Composite video output media CCTV camera to cover the range of bandwidth from five Hz to several MHz, the higher frequency is mainly determined by the resolution of the camera, and if black and white or color. For every 100 lines, with a bandwidth of about one MHz is required. Therefore, the 600 lines of the resolution camera to trace a video signal with a bandwidth of approximately 6MHz, this principle applies in both color and black and white cameras. However, color cameras are also to produce a color signal (chrominance) and output in black and white (luminance). Chrome signal is modulated carrier wave is a 4. 43MHz PAL because of the color signal, regardless of the definition of bandwidth is less than 5MHz.

Wireless camera Vs Cable camera

The important challenge, for any transmission method, is to be able to pass on the video signal with high fidelity, with minimum disturbance caused by surrounding interferences, from the source, either a Wireless-camera or a Cable camera, to the end user.

The ability to send video signals over a physical distance to the display of the instruments used to view is done in different ways, depending on transmission method selected.

Given the wide range of transmission technologies, we must examine the features and benefits of different kinds to decide in each particular case, which is best suited to perform the function required for successful monitoring and minimum cost.

Several methods exist for transmitting video coaxial cable, telephone line, cable CAT5 (Category 5) cable with adapters, fiber optic, microwave and radio frequency. Due to the needs of specific applications can be found in complex equipment, many video transmission technologies used in the same system of closed circuit television.

Cable Transmission (Cable camera)

All cables, no matter what their length or quality, produce problems when used for the transmission of video signals, the main problem being related to the wide bandwidth requirements of a video signal. All cables produce a loss of signal that is dependent primarily on the frequency, the higher the frequency, the higher the loss. This means that as a video signal travels along a cable it loses its high frequency components faster than its low frequency components. The result of this is a loss of the fine detail (definition) in the picture.

The human eye is very tolerant of errors of this type; a significant loss of detail is generally not objectionable, unless the loss is great. It is fortunate, since the loss of high frequency components is very high on the types of cables used in CCTV systems. For example, using the common coaxial cables URM70 or RG59, 50% of signal lost at 5 MHz to 200 meters of cable. To compensate for these losses, various amplifiers used. These provide the ability to selectively amplify high frequency components of the video signal to compensate for cable losses.

Cable Types

There are two main types of cable used for transmitting video signals, which are: Unbalanced (coaxial) and balanced (twisted pair). The construction of each is shown in diagrams 2 and 3. An unbalanced signal is one in which the signal level is a voltage referenced to ground. For instance a video signal from the camera is between 0.3 and 1.0 volts above zero (ground level). The shield is the ground level.

A balanced signal is a video signal that has been converted for transmission along a medium other than coaxial cable. Here the signal voltage is the difference between the voltages in each conductor.

External interference is taken by all types of cable. The rejection of this interference occurs in different ways. The coaxial cable is based on the central conductor, which, although considered by the outer copper. There are several types of coaxial cable and care must be taken to choose one with a braid of 95%. In the case of a twisted pair cable, interference picked up by the two leaders in the same direction on an equal footing. The video signal moves in the opposite direction to the two leaders. The operation can then be balanced by using the right type of amplifier. This can only react to the signal difference between the two leaders and is known as a differential amplifier.

Unbalanced (Coaxial) Cables

This type of cable is made in many different types of impedance. In this case impedance is measured between the inner conductor and the outer sheath. 75 Ohm impedance cable is the standard used in CCTV systems. Most video equipment is designed to operate at this impedance. Coaxial cables with an impedance of 75 Ohms are available in many different mechanical formats; including single wire armoured and irradiated PVC sheathed cable for direct burial, the cables available range in performance from relatively poor to excellent. Performance is normally measured in high frequency loss per 100 meters, the lower this loss figure, the less the distortion to the video signal. Therefore, higher quality cables should be used when transmitting the signal over long distances.

Another factor that should be considered carefully when selecting coaxial cables is the quality of the cable screen. This, as its name suggests, provides protection from interference for the centre core, as once interference enters the cable it is almost impossible to remove.

Balanced (Twisted Pair) Cables

In each pair of twisted pair is twisted with a twist slowly around one to two turns per meter. These cables are manufactured in different types of impedance from 100 to 150 ohms being the most common. Balanced cables have been used for many years in the largest cable networks in the world. When circumstances require, these benefits have on the coaxial cables of similar size. Twisted pair cables are often used where there would be an unacceptable loss due to a long series of coaxial cable.

The main advantages are:

1) The ability to reject unwanted interference.
2) Lower losses at high frequencies per unit length.
3) Smaller size.
4) Availability of multi-pair cables.
5) Lower cost.

Interests must be taken into account in relation to the price of the equipment of this type of transmission. Launch amplifier to convert the video signal is required for the camera and to reconstruct the control signal amplifier at the end of equalization.

Wireless Transmission (Wireless-camera)

To prevent the coaxial cables, if it is not practical for a monitoring solution of some houses, we can use two linked devices: a video transmitter and a receiver both established in the same preselected frequency and use of directional antennas a better connection. A video transmitter is included in the corresponding camera video wireless receiver purchased separately or part of the orchestra. The video signal from the wireless camera is sent by radio to the common frequency for the receiver that is connected by means of other elements of a surveillance system.

Radio Frequency (RF) is a reliable though short distance video transmission technology. It is regulated by national authority. For limited power dedicated installations, no special authorizations are required. For longer range and best reception unobstructed line of sight should be preferred, although normal walls are not an obstacle.

The main advantage of a wireless camera is that none of the coaxial cables should be installed so that less work is involved. It's easy and convenient way to move items to a new location, where appropriate. It is similar in principle to the mobile phone (with the exception of the directional antenna). Another advantage may be important when tracking objects of great value, is that the recording device is out of sight, hidden somewhere difficult for intruders to locate and destroy.

But wireless camera to be operated, continuous stream, usually by wire from a supply low voltage adapter (transformer) plugged into a standard wall outlet located somewhere near the camera location. (The solution of the battery is not recommended because of the short time between battery changes). Using a wireless camera is becoming increasingly popular where wiring methods are either impossible or difficult, and has been used successfully to reduce cabling costs even within large buildings. Environmental conditions in the region may affect its performance.

If more than one wireless camera is required, the amount of spectrum available limits the number of wireless cameras that can be deployed. If there are only four different frequencies can be used so that only four cameras can be installed on a given site.

The three different radio frequencies most used are:

•    2.4 GHz (Giga Hertz or 109 cycles per second) or
•    1.2 GHz or
•    900 MHz (Mega Hertz or 106 cycles per second)

Within each one of them a few different channels may be provided to avoid interference with other devices present nearby using the same frequency.

Radio signals can be disrupted by interference, nor inevitable (from competing devices at the same frequency) or it is generated in order to disrupt or interfere with the continuous monitoring of activities. It should be noted that the transmission path may be offensive: if this is a real risk, appropriate measures be taken to protect the integrity of the transmission. Although it could not cover the use of home monitoring, it is noted that the communication wireless camera can be subject to interception. To sum up, the Wireless-camera can be used almost anywhere, but the most common are discreet surveillance or baby sitter hidden cameras, door control and so on.

The choice of means of transmission depends on factors like distance, obstacles, environment in-house design, and cost, besides the option of mobility in the future must be considered. In addition, nearly all modes of transmission suffer from various forms of interference or loss to be minimized by good design.

However, for simple home surveillance purposes, the practical choice is probably limited to either coaxial Cable or Wireless-camera (radio) transmission. Finally, we recommendations wireless solution for a simple surveillance case, and to wired solutions for all the other cases.


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Offers You The Digital Surveillance System Advantage

Digital Surveillance System Advantage - Digital System

A home security camera offers you the ability to truly monitor what is going on at your home. If you have computer access, an Internet based home security camera offers you the digital surveillance system advantage. Whether you are at home, at the office or lounging on the beach you can access high quality digital images of your home through the Internet.

Because the technology has become less expensive, many home owners can purchase a great digital surveillance system to protect their loved ones and their property.  Prices start at less than $100 and can go as high as $1800 or more.

Business owners of establishments like bars, night clubs, restaurants, clothing shops, etc., can also realize a great benefit from a digital security system. A DVR security setup can handle up to 16 cameras, which would cover all the angles of your property inside and out as an effective theft deterrent and silent, reliable witness to any crime or misbehaving that occurs.

The components of digital surveillance systems are software and hardware that collect and send the images and audio by wireless transmission, or a fiber optic cable over any internet protocol network.  Cameras used in a digital surveillance system can have an IP address to allow for full accessibility to the internet.

When choosing a camera monitoring system, you will need to determine whether you want a security system that offers black and white images or color images. Systems that offer color images will usually offer the clearest images; however, in some cases these systems may not be as higher as black and white image systems. In very advanced systems, the camera will automatically switch between color images and black and white images. For example, during daylight hours, monitoring will be recorded in color while black and white images will be recorded during the evening hours.

Another option worth considering is camera systems that provide infrared solutions. These systems are highly advantageous for recording in the dark when it could be difficult to make out much detail, even with black and white images.

They are not only monitoring your property but also provide the crucial evidence that may be necessary to assist authorities in actually catching the guy who tried to break into your property. With old-fashioned systems, the criminal very well may be frightened away only to break into someone else's property or come back another time.

With a digital surveillance system, you have remote access from anywhere as long as you have a computer. Being able to keep an eye on your home or business is easier and more affordable than ever.  It’s only a matter of you assessing the level of a security system that you need, and doing a little comparison shopping to find the best deal.  Because the digital system you do not have to worry about supplying videotapes that can be expensive and take up a lot of storage space.

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Understanding Animal Camera Surveillance

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In general, Animal surveillance camera has a goal to control the welfare of animals that may live in a large area is difficult to monitor from a single point of view.

It is important to every breeder is the healthy condition of each animal, to detect and cure any disease condition as soon as observed and to avoid the epidemic spread. Observation of a strange animal behavior at the beginning can help find out.

Understanding Animal camera surveillance and should be selected to provide high quality information and installed with certain redundancy to ensure full coverage area and every animal.

However, the number of cameras, their features and capabilities and their relationships should be studied and implemented specifically to convey the views of the most important for those who are responsible for maintaining the needs of animals. You know you and farm animals. Nobody can imagine you needs better than yourself!

For large establishments with a large number of animals in big areas, needs multiplied, if adequate supervision must be ensured.

Monitoring of large space must be established, to control the view of several cameras. If the operator defined for constant monitoring of live stock, swinging with PTZ cameras (pan-tele-zoom) capabilities needed to cover larger areas.

For the simplest case of pet control, limited to movement within a limited space, maybe one or two cameras will cover all needs. Agriculture which kept pets on a full board to let the owners go on vacation, offers several web services still cams, to enable employers sometimes watch their animals from a distance via the Internet.

For night reconnaissance, good enough light or infrared illumination must be satisfied everywhere, if not annoying habit of animals, or equipped with night vision cameras to be used.
Secondary recording capability may be important, just as a backup to investigate the dynamics and then whatever happens.

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CCTV Video Camera - CCTV Digital Video Camera

VoIP - Voice Over Internet

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CCTV Video Camera - CCTV Digital Video Camera

CCTV is increased in the areas where increased need for security, such as a banks, airports and town center. CCTV was generally developed in banks for increased security but now after time in general video surveillance and home security it is also used. For residential applications, a CCTV digital video camera can protect your home and give you the peace of mind even when you are a way of knowing that things are secure. For commercial applications, nothing provides cost effective security and surveillance as well as documentation than a CCTV digital video recorder.

The primary work of a CCTV camera is to convert light into a video signal. All CCTV cameras require an optical lens to focus the light onto an image sensor located directly behind the lens inside the CCTV camera. The function of the lens is to limit and focus light at the image sensor of the CCTV camera. A lens can automatically control the amount of light who reaches the imaging sensor, are used in where the amount of light varies and varying weather.

CCTV was used in reference to video cameras that were each connected to a video recorder. Each camera has a video transmission cable, usually a coaxial type RG-59 cable, which runs from the camera to the recording unit and monitor. The only way to receive the camera’s signal was to be in a closed circuit with it via the video transmission cable. Since these cameras didn’t broadcast their video signals publicly, they were called Closed Circuit Television or CCTV.

On these units, the CCTV digital video unit is still connected to everyone camera in the system; however, as mentioned earlier they may now be connected by a specific radio signal transmission.

The DSP interprets the digital data sent to it by each digital video camera and then creates a digital video file. Unprocessed digital video files can become extremely large in a very short period of recording time, so the DSP usually applies some sort of Compression/Decompression or CODEC utility. This CODEC utility processed the digital data in such a way as to greatly reduce the size of the file while still maintaining high video quality.

In the security camera industry, a CCTV digital video recorder is usually thought of as one of three integral components in a digital video security system. The other two are the digital video camera(s) and an LCD monitor. For residential or commercial standalone digital video CCTV systems, the DVR is basically the equivalent of a personal computer hard disk drive connected to a high specialized type of computer processor called a Digital Signal Processor or DSP.

This standalone CCTV DVRs today normally have storage capacities that range from 250 gigabytes to over 1 Terabyte. This coupled with modern CODEC utilities this translates to longer periods between overwrites when a disk becomes full and even greater capacity to store multiple cameras at once.

Any CCTV camera installation process must determine the number of cameras required and must take into account the main fields of view and the recording needs. The other conditions to consider are the amount of lighting available, the areas that require live video monitoring, and the amount of time one needs to keep the video files.

You will have to choose Types of CCTV cameras depending on its usage, location of placement, and the time of the day during which it will be used. The Indoor Dome Cameras are used for inside applications, and are mounted on ceilings. These can be configured for day/night, standard color, or infrared. The common locations for Outdoor Dome Cameras are entry and exit points, with fewer amounts of night lighting. The Day/Night Cameras are useful in conditions of low light. In the daytime, these cameras records in standard color and then switch to low–lux black and white mode during the night.

Infrared cameras used in conditions where there is now available light. The camera does a black and white recording when the infrared LEDs get illuminated.

PTZ Cameras or “Pan – Tilt – Zoom” cameras can automatically zoom in all directions. These are mounted on such a stand that these can turn full 360 degrees in order to track the object in focus. These can also turn (or tilt) to an angle to the base for the same purpose.

Choosing the kind of CCTV [closed circuit TV] video camera is hard, but if you have a little knowledge of the problems than at least you know the kind of queries you ought to request. Conversing with a specialized sales representative may also be educating when they are in advance with the particulars. Selecting the most appropriate CCTV systems can be challenging. However, understanding the problems ought to allow it to be a simpler process.


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VoIP - Voice Over Internet

VoIP - Voice Over Internet

From early starts in 1973, the capability to transmit voice messages over the Internet was added over the years, the way we make phone calls is changing. Take long distance calls, for Many service providers are already using a technology called Voice Over IP or VOIP for short, Other expressions for the same subject are also Voice over Broadband, Broadband Phone, Broadband Telephony, IP Telephony and Internet Telephony.

VoIP stands for Voice over Internet Protocol, is a method for turning analogue audio signals into digital data that can be transferred over the internet. The digital signal is then converted at the other end back to a voice signal that the other party can hear. When you use a phone with an adapter the calls are placed just like a regular telephone. You first hear a dial tone than the call is made. You are also able to place a call directly from your computer using a conventional telephone or microphone.

Integration of VoIP with other services that are available for the Internet includes video conversation, audio conferencing, and data file exchange, sharing address books, and finding out if additional partners (friends or colleagues) are present online.

There may be differences about the charges (or the lack of them) for long range connections who different service providers may or may not debit to their customers. Some services are offered at no cost, but not all the facilities normally proposed by regular phone companies are available to Voice IP users.

Your existing incoming high-speed Internet connection should be sufficient but the higher the connectivity the better the signal. In terms of hardware, you can hook up an inexpensive microphone to your computer or connect a phone directly to a VoIP telephone adaptor (ATA). ATA takes the analogue signal from your standard phone and turns it into a digital signal that ready for transmission over the internet. Some ATA's (gateways) come with additional software that is loaded onto a host computer, enabling you to configure it for VOIP accurately. Alternatively, you can use a phone specially made to work with Internet Voice. This is called an SIP Phone. Each SIP phone is a network endpoint, and voice is routed via its IP address. It allows a DID (direct inward dialing) number to move with a user. You can move, add or remove stations and never have to call your interconnect/PBX service company. SIP phones also allow full use of advanced features like voice mail to e-mail and auto attendant.

Not all VoIP services provide connections with centers of emergency services. Emergency call numbers of Public telephone services are generally unreachable through the Internet except if special procedures are in place.

Moreover, VoIP reliability is put in the cause because occasional power blackouts may hinder transmission as these services are not backed up as phone companies are.

It is difficult to locate geographically network users who are using IP Telephony. Therefore, Emergency Calls cannot be easily routed to a call center near the origin except if the caller can provide an address.

Although there are many advantages of VoIP, present are also quite a few disadvantages.

• The problem of privacy of voice transmission over VoIP is still unlocked as encryption is adopted only by some service providers. Therefore, it is believed that eavesdropping of Voice IP conversation is possible, using open source solutions.
• If for any reason, you lose your internet connection. You will not have to phone service. Therefore, you must use a cellular phone should this type of situation arise.
• If your network has a large quantity of computers connected, and they are all using the internet at the same Your TIME VoIP quality will generally be less than desirable. One way to avoid this situation is to invest in an Ethernet.
• Audio quality is one of the largest issues. No matter what your VoIP service offers you, the basic role of any phone is voicing communication. If the quality is not up to par, next there is absolutely no point to all the bells and whistles that comes with the service. If you have a lot of background noise, then a VoIP that can handle music, video, caller ID and a variety of other advanced features is practically useless. The type of phone you have, as well as the frequency can affect the quality of your VoIP. Many people believe that the higher a phone's frequency is, the improved the quality of VoIP. However, in some instances, a lower frequency phone may fit your connection better; you may want to try a phone if you are experiencing a lot of audio feedback.

Even with all the advancements of VoIP, there are times when the audio quality suffers. Since VoIP relies completely on the internet connection, anytime the internet suffers so will the VoIP.

If you have decided that a VOIP phone system is the right step, next you need to determine which of your accessible telephone equipment you are able to keep. The potential cost savings that can be made through using any existing digital equipment are huge. Many digital phone systems can be IP enabled using minor hardware additions and software upgrades.

When shopping around for potential systems you need to be sure of the features they provide as standard and, which are optional cost extras. You also need to be certain of exactly. What is included with the system? Many suppliers claim to include everything you need, but standard components can vary from one company to the other. So you need to sure you are comparing equivalent systems when approaching potential suppliers.

You will also need to enquire about the compatibility of existing equipment. The technology used in many VOIP systems may affect the implementation of any existing telephone hardware.

You will also need to ensure that any devices such as fax machines, credit card processors, and security systems, etc. can be integrated into your new VOIP phone system. You should make any potential vendor aware of such devices, so they can provide you with a suitable phone system for your requirements.

Overall, VoIP - Voice over Internet is a great low cost alternative for communication. VoIP is not passing through, they are here to stay. Major corporations have done some significant research to fix the disadvantages of VoIP service; it will soon be accepted by everyone as an acceptable alternative to PSTN.

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