Belden CDT Electronics extends sweep testing of Brilliance® precision video cables to 4.5 ghz

Belden CDT has become the first cable manufacturer to perform sweep testing to 4.5 GHz on every reel of SDI cable and provide certification to assure unequalled levels of cable signal integrity and reliability, with lower return loss (RL) at higher frequencies. The enhanced testing is currently being performed with three of Belden’s most popular precision video coaxial cables for HDTV/SDI – Belden Brilliance 1505A, 1855A, and 1694A – and will soon be expanded to additional products.

Belden CDT Electronics Division, a unit of Belden CDT Inc., and a world leader in the development of specialty cable products for A/V, broadcast and entertainment applications, has announced the extension of its SDI coaxial cables' performance specifications from 3 GHz to 4.5 GHz – with every reel being sweep tested for return loss and certified to the new, higher frequency.

This extension is designed to assure broadcasters, leading-edge broadcast equipment manufacturers and the standards bodies, of high performance and reliability as they begin to migrate from the existing 1080i (interlaced) SDI format to the emerging 1080p (progressive) format, protocols and equipment, which require twice the bandwidth of 1080i.

According to Marty Van Der Burgt, senior product engineering project manager at Belden CDT Electronics Division, we are in the midst of a digital revolution: “Many broadcasters, television production studios and post-production enterprises have adopted high definition, serial digital imaging (HD/SDI) as their format of choice because of its superior performance and other advantages. Precision digital video is processed in real time and is extremely stable, which reduces equipment adjustments and allows copies or reproductions to retain the same quality as the original. Moreover, signal degradation is virtually eliminated and noise immunity is greatly improved. Digital technology not only promises to improve picture and sound quality, but also paves the way for interactive on-demand TV and other digital services.

“In the 1080i (interlaced) format, the image resolution is 1920x1080 pixels, sent at 60 interlaced frames per second. In the 1080p (progressive) format, the image resolution is the same but is sent at 60 complete frames per second. Thus, in the progressive format, the complete image updates every 1/60th of a second and in the interlaced format, only half of the image updates every 1/60th of a second. As a result, progressive images result in better image definition and quality.”

Cable manufacturing consistency and quality are both key to achieve minimal return loss. Good practice requires testing to the third harmonic of the operating frequency. For serial, single cable 1080p, that means testing to a frequency of 4.5 GHz. This 1080p format is expected to transmit serial digital video signals at 2.97 Gb/s, requiring an operating frequency of 1.485 GHz. This translates to a shorter wavelength and a greater chance that inconsistently manufactured cables will choke off the signal with a high level of return loss. This may be caused by even the slightest irregularity in the cable manufacturing process. A slightly bent shaft, bad bearing or uneven cable tension, for example, can cause reflection and affect the signal wavelength. Therefore, utmost consistency and control in the manufacturing process is essential to the reliability of the cable’s signal transmission at high frequencies and to minimize return loss.

Werner Eich, Marketing Manager Entertainment Europe for Belden CDT explains: “We are preparing for the future. As a pioneer and leader in cable technology, Belden CDT Electronics Division has always taken a stringent approach to cable quality assurance. Rather than simply inspect and test random batches of cables after manufacturing, Belden begins its quality process in the product development and manufacturing stages.

This "Design for Manufacturability" approach, combined with statistical quality control of manufacturing processes, and state-of-the-art manufacturing and testing equipment, ensure that Belden cables are manufactured in such a consistent manner as to guarantee superior performance and reliability.”

For more information about Belden’s 4.5GHz sweep testing of precision video cables, please contact Belden CDT Europe, P.O. Box 9, 5900 AA, Venlo, The Netherlands or call: +31 (0)77 - 3878555. Fax: +31 (0)77 - 3878488. Or visit the Web site: www.belden.com.