Introduction to AHD Cameras and DVRs

During old traditional surveillance system's upgrading and replacing, can't balance between achieving high definition surveillance and combining old traditional analog system become headache for users. In standard analog surveillance system, 960H is the highest resolution, to achieve much higher resolution becomes impossible mission for traditional surveillance system since its limitation from its technology.

If adopts all high definition (HD) IP camera, the entire system need to replace, this will not only generate high labor cost, but also significantly increased the project budget.

AHD stands for analog high definition, AHD's birth, is to solve the transmission distance limitations of existing HD-SDI solution. As one of new HD analog solution, AHD supports video transmission over traditional 75-3 coaxial cable up to 500 meters, and it becomes another alternative for HD analog solution. By the way, it inherits and carries forward advantages of traditional analog solution, video signal are uncompressed, keep all the original video details, to truly achieve high definition uncompressed lossless, no video latency effect.

Similar to other HD analog solutions, through using the progressive scan CMOS image sensor, the AHD camera can deliver 1.0 megapixel, 1.3 megapixel, 2 megapixel resolution, added with ICR filter, the camera achieve true day/night video surveillance; and same like the traditional analog system, AHD products support plug-and-play installation, easy to use.

Introduction to AHD Cameras

Recently, some companies offer AHD analog cameras which deliver 1.0 megapixel and 1.3 megapixel resolution. 1.0 megapixel AHD camera adopts OV9712 + NVP2431H, and 1.3 megapixel adopts SONY IMX238 + NVP2430H chipsets.

• 1.3M CMOS sensor support
• Programmable AE/AWB/AF detection
• 3D-NR(Noise Reduction) for NVP2430H
• 3D-NR(Noise Reduction) for AHD 1.0
• Output for NVP2431H
• Defog
• Digital wide dynamic range (DWDR)
• Low shutter
• User defined OSD
• Dead pixel compensation (live/static)
• On chip MCU & SDRAM

AHD chipsets are from Korean company - Nextchip, the company launches AHD chipsets (NVP2430H/NVP2431H) which can work with 1.3 megapixel progressive scan CMOS image sensor. The new HD-AHD chipsets are designed to meet the demands of new trend in CCTV market, it is suitable for both analog HD camera and cost-effective HD-SDI applications. The main concept of NVP2430H is supporting 1.3M CMOS sensor and output I/F as analog 1280H(CVBS/COMET), AHD 1.0(720p) and HD-SDI 720p. NVP2431H is supporting 1.3M CMOS sensor and output I/F as analog 1280H(CVBS/COMET) and AHD 1.0 (720p).

Introduction to AHD DVR

Currently, we still haven't seen the real products of AHD DVR. Since Nextchip is the AHD solution provider, it also offers AHD codec chipset - NVP6114. NVP6114 is designed to encode and record the video footage from AHD cameras. AHD DVR based on NVP6114 can support 4 channel AHD and 9 channel audio codec. It can work with 1.0 megapixel and 1.3 megapixel AHD cameras, deliver high quality images.

NVP6114 includes 4-Channel AHD1.0 RX and 9-Channel Audio Codec. 4-Channel AHD1.0 RX delivers high quality images. It accepts separate 4 CVBS/COMET/AHD1.0 inputs from Camera and the other video signal sources. It digitizes and decodes NTSC/PAL/COMET/AHD1.0 video signal into digital video signal which represents 8-bit BT.656/BT.656like 4:2:2 byte interleave format with 27/36/54/72/108/144MHz multiplexed. Especially, It is able to use same transmission cable with conventional one for COMET(SD level) and AHD 1.0 (HD level), and they provide the superior image quality by minimizing the interference when separating Y and C. 9-Channel Audio Codec is 8-Channel Voice/1-Channel Mic PCM Codec which handles voice band signals(300Hz~3400Hz) with 8bit/16bit linear PCM, 8bit G.711(u-law, a-law) PCM. Built-in audio controller can generate digital outputs for recording/mixing and accepts digital input for playback. 4-Channel Coaxial Communication Protocol communicates between controller(DVR) and camera on the video signal through coaxial cable. COMET is Composite Video of Enhanced Technology in SD video by NEXTCHIP. AHD is a video transmission technology in HD video by NEXTCHIP.