Security cameras - analogue security for coax cables

Security cameras - analogue security for coax cables

• 420TVL - basic resolution with 420 TV lines for monitoring areas such as entrances and gardens for movement.
• 480TVL - standard resolution with 480 TV lines for monitoring areas such as entrances and gardens for movement.
• 700TVL - high definition with 700 lines for monitoring entrances and gardens, as well as large areas such as parking areas and where there is greater traffic of people or cars. Good resolution which is able to capture number plates and better face definition.
• 800TVL - very high definition with 800 lines for monitoring entrances and gardens, as well as large areas such as parking areas and where there is greater traffic of people or cars. Very good  resolution which is able to capture number plates and better face definition.

Colour vs Black/White analogue cameras

Image detail is captured in black and white and users do not require colour to capture images in good detail. Colour makes it easier to see moving objects in daylight, and makes images more realistic to view.

Cameras switch to black/white at night for better clarity. Infra red light, usually provided by LEDS, captures images in monochrome.

The strength of the Infra Red light is defined as a distance in meters (or feet). Infra Red that covers 30meter will be brighter than 10meter, where the 30m IR will illuminate objects up to 30m away from the camera.

Smart IR is a technology built into some security cameras that adjusts the intensity of the camera's infrared LEDs to compensate for the distance of an object so that the infrared does not overexpose the object.

Advantages of analogue cameras

• A wide variety of replacements are available
• Cheaper than network cameras
• Good infra-red night vision from most analogue cameras
• DVR Bundles are great value for money
• The image can be viewed on a PC or mobile device using a DVR device
• A network is not required and a television set or computer monitor connects diretly to the DVR device

Disadvantages

• Lower resolution images compared to Megapixel IP cameras may lack definition
• High resolution cameras are still lower resolution than network cameras
• Requires a separate DVR to convert video to digital format for digital storage and for Internet viewing

What is the difference between CVBS, AHD, HD CVI, HDTVI connections?

HD CCTV  is a new open standard for trait HD digital video over coaxial cable. HD CCTV doesn’t require changing the existing coaxial cable infrastructure and it is an only a matter of replacing the camera and a security camera recorder.

• CVBS stands for "Composite Video Blanking and Sync”. It is a conventional analog signal delivered through an analog  BNC connector. It also can be delivered through an RCA connector or other types (older cameras sometimes used a PL-259 connector). CVBS  signal can support max. 960H video resolution. 960H represents the number of horizontal pixels in a video signal transmitted from a camera or received by a security camera recorder DVR (Digital Video Recorder). 960H represent 960 x 576 (PAL) or 960 x 480 (NTSC) pixels, you can compare it with the lower D1 resolution providing 720 x 576 pixels (PAL), or 720 x 480 pixels (NTSC).
• AHD stands for “Analog High Definition” and means an analog closed-circuit television video surveillance standard that uses a coax cable to transmit HD 720P and 1080P video from a security camera to a security camera recorder DVR (Digital Video Recorder).
• HD-TVI means “High DefinitionTransport Video Interface”, it is an Analog CCTV standard transmitted over coax supporting HD 720P to 3MP Video signal in real-time. HDTVI can support long distance video transmission reaching up to 500 meters.
• HD-CVI (High Definition Composite Video Interface), an analog transmission standard based over-coaxial-cable delivering two HD video formats: 1920H or called otherwise Full HD 1080P (1920×1080) & 1280H or called otherwise 720P (1280×720) through progressive scanning.