Automotive HD link enables the use of standard interconnects

Renesas Electronics Corp. has introduced its automotive HD link (AHL) technology for automotive cameras that enables the transmission of high-definition (HD) video over low-cost cables and connectors that currently support standard-definition video. The AHL can be paired with other Renesas products, such as the R-Car automotive SoCs, RH850 microcontrollers, automotive power management ICs, and analog components to implement vehicle safety features.

The new RAA279971 AHL encoder and RAA279972 decoder use a modulated analog signal to transmit the video, which enables transmission rates 10 times less than required to transmit HD signals digitally. Renesas said the lower transmission rate means that traditional twisted pair cables and standard connectors can be used, as well as existing analog video cables and connectors. This is in comparison to digital links such as SerDes that require heavily shielded cables and high-end connectors that cost significantly more than those for AHL, may require replacement after five to seven years, and are difficult to route due to bending radius limitations, said the company.

The AHL is said to be robust against noise and has a bi-directional control channel that operates independent of the video data and can initialize, program, and monitor, the camera module. The AHL can control the camera simultaneously over the same pair of wires (UTP) during video transmission, which is both a performance and cost-reducing feature, said Renesas.

In addition, “in a rear view camera application, a digital link will degrade due to a failure in the cable harness or connector assembly, as weak signals can cause macroblocks to appear, hiding large portions of the viewing area. Using the same cable under the same conditions for comparison, the AHL link will present a slight change in video color or contrast, but all pixels will appear on the screen, and the image will precisely identify an object or person behind the vehicle,” said the company.

The AHL supports resolutions from VGA up to 720 p/60 or 1080p /30 to implement non-standard vertical resolutions, not just the TV video standard 16:9 resolutions. It also provides MIPI-CSI2, BT656, and DVP inputs and outputs to support old and new image sensors. It only requires a 27-MHz crystal clock, with internal PLLs, to generate the necessary clock frequencies for higher resolutions.

The automotive HD link devices and evaluation boards (RTKA279971DA2000BU AHL Encoder and the RTKA279972DA1000BU AHL Decoder) are available now.

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