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HDcctv FAQ'S
1. What is HDcctv?
HDcctv is an alternative to IP and offers 1280x720 resolution over standard coax! HDcctv transmits an HD digital signal, called High Definition Serial
Digital Interface (HD-SDI), uncompressed, over coax at a constant 30 FPS.
The HD-SDI digital signal is then received by the DVR and compressed into H.264
or MPEG-4. This new technology is significant to the CCTV Industry and
will be a major format for dealers and installers who do not want to use
IP for various reasons. HD-SDI was invented by SMPTE for use by
the Broadcast Industry and is used by all HD newscasts, sporting events, etc.
2. What is SDI?
Serial Digital Interface. It is a standard for digital video transmission over coaxial cable. The most common data speed is 270 megabits per second (Mbps). However, speeds up to 540 Mbps are theoretically possible. Standard 75 ohm cable is used. This is the same type of coaxial cable used in most home television installations.
3. What is HD?
HD resolution is 720P or 1080i/P. 720P equates to one megapixel and 1080 equates to two megapixel.
4. What is the difference between 720P vs 1080i? Which is better?
P = Progressive vs I = Interlaced
1080i (Interlaced) represents 1,080 lines of resolution scanned in alternate fields consisting of 540 lines each. 1080i is the most commonly used HDTV format, and has been adopted by most television broadcast, cable and satellite outlets as their HDTV broadcast standard.
720P (Progressive) represents 720 lines of resolution scanned sequentially. In other words, all lines are scanned progressively, providing a more detailed high definition video image compared to interlaced display technology of the same resolution. Progressive scanning reduces the need to prevent flicker by filtering out fine details, so spatial (sharpness) resolution is much closer to 1080i than the number of scanned lines would suggest. Because of the Progressive scanning, recording at 720P has a better resolution than 1080i.
5. Is HDcctv IP?
HDcctv has nothing to do with IP cameras. No bandwidth calculations, no compression issues. It is NOT an IP camera in anyway and therefore does not use an Ethernet cable.
6. Can I install an HDcctv camera to an analog DVR?
No. You will need to have a DVR that accepts the HD-SDI signal. Current analog DVR's do not accept accept this signal and therefore will require a specific DVR made for this new technology. These 'HDcctv' DVR's will accept both the HD-SDI signal and current analog inputs making a switch/upgrade very easy.
7. What type of cable can I use?
RG-59, RG-6, RG-11 or fiber optics. CAT5e and/or CAT6 is NEVER used for HDcctv cameras. Repeat....HDcctv NEVER uses CAT5e or CAT6.
8. What are the specifications that I need for the cable?
Not all cable is created equal! Do not expect to get the most of HDcctv is you are still using 'cheap, economic cable' for your installation jobs. If you buy low end, the results are most likely to be the same. That being said, please make sure the cable meets these specifications:
| Frequency | Attenuation / 100ft
| Attenuation / 100m
| 1GHz (1000MHz)
| Less than 6db
| Less than 20db
|
The smaller the db loss per 100 ft, the longer the transmission over coax
IMPEDANCE: 75 ohm
In general, the impedance for transmission of analog cameras is 75 olm. 75 olm is also used in HDcctv cameras.
9. Will it work over CAT5e or CAT6?
NO. HDcctv will not work with Ethernet cable because it will not support the data transmission required and HDcctv cameras are NOT IP cameras.
10. What is the transmission distance of SDI over coax?
300-450 feet per run is standard, however the quality and condition of the coax plays a significant role in distance. There are repeaters available to extend the distance.
RG-59 - up to 300 feet. Repeaters can be used to boost the distance.
RG-6 - up to 800 feet between HD camera and HD DVR.
RG-11 - 800 to 1,000 feet.
11. How much data is transmitted over coax?
1.485 Gb/s per run.
12. Can I use the existing coax that is in place?
In many cases...YES. But please keep in mind the quality and condition of the coax. Replacement of some coax may be needed in order to achieve maximum distance and optimum results.
13. Is there any re-training required from an analog installation?
HDcctv and analog installation are the same. If you know how to install analog, you know how to install HDcctv. The difference is simply in the the equipment.
14. What is the storage requirement?
720P runs at about 25K/frame, which is about the same as 1 CIF JPEG recording.
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HDcctv Frequently Asked Questions
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