Renesas Electronics Corporation has introduced the newest device in its Automotive HD Link (AHL) portfolio that enables automotive manufacturers to deliver high-definition video over low-cost cables and connectors. The new RAA279974 4-channel AHL video decoder processes four input sources simultaneously, making it a cost-effective solution for surround vision and multi-camera applications.
Renesas' AHL technology uses a modulated analog signal to transmit video. The frequency is therefore 10 times lower than digital transmission solutions available on the market today (~37MHz vs. >3GHz), making it robust against noise and allowing longer transmission distances (20-30m) with pair cables Unshielded braided and standard connectors. Existing standard definition analog video cables and connectors can also be employed. Using unshielded twisted pair cables not only reduces cost, but is also easier to route throughout the vehicle and offers lighter weight for better energy efficiency and performance. Digital links like SerDes require heavily shielded cables and high-end connectors that cost significantly more than those for AHL and may require replacement after five to seven years.
The RAA279974 completes the AHL product family consisting of the RAA279971, a single-channel AHL video encoder, and the RAA279972, a single-channel AHL video decoder. The RAA279974 is an important addition to the AHL family as most OEMs want to support multiple cameras in vehicles for applications such as surround-view parking assistance monitors. The AHL can be paired with R-Car Automotive SoCs, RH850 MCUs, automotive PMICs, and analog components to cost-effectively implement various safety features in virtually any vehicle. Renesas provides several winning combinations that combine these components to enable manufacturers to quickly implement pre-tested video designs.
AHL is robust against noise and provides excellent image quality. There is no noticeable difference in image quality when compared to a pure digital video image. Due to the fundamental nature of an analog signal, an AHL video transmission can withstand noise and interference. The image may degrade slightly, but there will still be a live image to view. With a digital link, any noise/interference will result in a complete loss of the image.
Key features of AHL include: Supports VGA resolutions up to 720p/60 or 1080p/30 for flexibility in implementing non-standard vertical resolutions (not just standard 16:9 TV video resolutions); MIPI-CSI2, BT656, and DVP inputs and outputs provide a flexible interface to support a variety of image sensors; AHL does not require compression like an Ethernet system, so there is no video latency; Requires only 27MHz crystal clock, with internal PLLs capable of generating the clock frequencies required for higher resolutions, reducing costs; AHL passed EMC/EMI BCI and CISPR25 tests using UTP cables; MIPI-CSI2 output with Virtual Channel allows 4 channels of video to be sent via a single data bus interface to the SoC (save input ports on the SoC);
AHL RAA279974 four-channel decoder samples and evaluation boards are available today. Renesas also offers the RTKA279974ZK0000BU Camera Kit Bundle evaluation system, which includes four AHL cameras integrated with the RAA279971 AHL encoder.
