Meeting HDTV requirements for the future:
Belden HDTV cables exceed the standard

Belden’s range of Brilliance™ broadcast video coax cables, designed for maximum bandwidth, minimum return loss and minimum attenuation loss already meet the very tight specifications for electrical properties. Now to make them ideally suited for 1080P HDTV/SDI applications, their performance specifications are extended from 3GHz to 4.5 GHz. In addition, every reel is sweep tested for return loss and certified to the new, higher frequency.

According to Marketing Manager Entertainment Europe, Werner Eich, Belden is the first cable manufacturer to perform sweep testing and certification to meet this emerging format for Belden: “HD 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. HD technology not only promises to improve picture and sound quality, but also paves the way for interactive on-demand TV and other digital services.

“Therefore, broadcast camera and video cables need to deliver top performance, whilst at the same time meeting extended international and European standards.”

One of the more than seven HD formats that currently exist on the market is 1080i (interlaced) format, with an image resolution of 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.

It is for this reason that Belden became the first cable manufacturer to increase its sweep testing from 3 GHz to 4.5 GHz for all coaxes designed for maximum bandwidth, minimum return loss and minimum attenuation loss. These cables already meet the very tight specifications for electrical properties and are ideally suited for both analog and digital video in broadcast, post-production and other critical video applications.

In addition, Belden performs 100% sweep testing to 4.5 GHz on every reel of HD cable and provides 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 this will soon be expanded to additional products.

Positive test for Brilliance™ broadcast HD video coaxes

An independent test laboratory took an in-depth look at the HD performance of the video coaxes used in TV studios. Cables were tested for return loss, attenuation and maximum cable run on HD (1080i and 720p).

The most popular precision video coaxial cables for HDTV/ SDI, Belden Brilliance™ 179DT, 1855A, 1855ENH, 1505A, 1505F, 1694A and 7731A were subjected to extended testing. In the end results all BeldenCable™ products delivered performance values that exceeded those listed in Belden's own catalogues.

Werner Eich: “Belden is preparing for the future. As a pioneer and leader in cable technology, this Belden division has always taken a stringent approach to cable quality assurance. Rather than simply inspect and test 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.”

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