MOST® Testing with Cable Model

Application Note for MOST150 Coax Physical Standard is Available

MOST® Testing with Cable Model

Top view of the test board with remote control

The MOST Cooperation (MOSTCO) – the standardization organization for the leading automotive multimedia network Media Oriented Systems Transport (MOST) – announces that an application note is available that describes a test board for the MOST150 cPHY that uses a cable model based on available discrete components. Set up by the Working Group Physical Layer according to the compliance measurement guideline, this application note is available for MOSTCO members to be used for compliance checking. The application note refers to the released MOST150 Electrical Physical Layer Sub-Specification Rev. 1.0 based on coaxial cable. This MOST150 coax physical standard complements the existing MOST150 optical physical layer in the infotainment domain, especially for OEMs who have strong preferences for an electrical physical layer. In addition, this new standard opens the way for using MOST in other vehicle domains. For example, it fits well in the driver assistance domain, as this physical layer is able to provide bi-directional communication and power supply on a single coaxial cable.

The test board used is a series of distinct functional blocks: transmitters, cable transmission line (TL) models, multiplexer, noise adder (for emulation of reflections), directional splitter and amplifier for the return signal. Several options can be chosen by 24 DIP switches or with a remote control through a USB port of a PC. The cable model was verified in the time and frequency domain with a cable having the same attenuation curve as the worst case curve in the cPHY MOST150 Specification. Three transmission line models can be tested. A very short one, and two of maximum length, one of which is close to ideal attenuation at that length, and one that has maximal deviation according to the cPHY spec. Worst case reflections (return-loss) that can occur in the cable itself generate cross-talk in full-duplex mode. This can be emulated for said three transmission line models. On top of that, the worst case reflection at the receiving side, also generating cross-talk, can be added to generate the absolute combination of worst case conditions, and evaluate the proper operation of the cPHY receiver under test.

Image source: EqcoLogic NV

About MOST Technology
MOST (Media Oriented Systems Transport) is a multimedia networking technology optimized for use in cars and other applications. It enables the transport of high Quality of Service audio and video together with packet data and real-time control over a single transmission medium. MOST can use plastic optical fibers (POF), coax based electrical physical layer, and shielded and unshielded twisted pair (STP/UTP) copper wires that meet automotive environmental requirements. Today, MOST is used in over 125 car models as the communication backbone for their information and entertainment equipment.

About MOST Cooperation
The MOST Cooperation (MOSTCO) is the organization through which MOST Technology is standardized and refined so that it continues to stay abreast of the latest industry requirements. Today it consists of 16 international carmakers and more than 60 key component suppliers. They have joined together to work with the MOST Technology and to contribute to its innovation. The MOST Cooperation is prepared to embrace efforts to further develop and standardize the technology for other industries and to establish the corresponding work structures. The MOST Cooperation was founded in 1998 to standardize MOST Technology as a global standard for multimedia networking. Audi, BMW, Daimler, HARMAN and SMSC are its core partners and constitute its Steering Committee. For more information see http://www.mostcooperation.com.

Kontakt:
MOST Cooperation
Mandy Ahlendorf
Bannwaldallee 48
76185 Karlsruhe
+49 8151 55009 11
mostco_pr@alvacon.com
http://www.mostcooperation.com

Pressekontakt:
alvacon pr
Mandy Ahlendorf
Maximilianstraße 8
82319 Starnberg
+49815155500911
pr@alvacon.com
http://www.alvacon.com