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Advanced Multi Room Video and Distributed Audio System on
category 5 wires This article describes an advanced Multi Room Video and Distributed Audio System on category 5 wires. A brief overview of the traditional approach is presented and its problems and limitations are identified. The advanced approach that provides higher performance and greater flexibility is described in detail. The benefits and advantages of this novel approach are also explained. |
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Introduction
The advent of consumer electronics products such as DSS, DVD players, CD carousels, personal computers, hard disk based MP3 jukeboxes and home theaters in the last two decades have created a need for distributing audio and video signals to multiple rooms in the home. Traditionally all the electronics equipment is located in one central area like the family room or an A/V equipment closet and signals are distributed to all the rooms.
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Figure 1 shows an example of audio and video distribution using the traditional approach which involves coaxial cable for video signals, heavy gauge speaker wires and category 5 wires for Infra-Red remotes and keypads. In this example, there are 5 audio/video zones and 5 audio only zones. The head-end equipment consists of a 6 A/V source 4 zone controller with and expansion unit to take care of the additional zones. It also has two 8 channel power amplifiers to support all the speakers in the zones. The actual audio and video sources such as the DVD players, CD juke boxes, etc. are not shown in the figure. The keypads from all the locations are centrally connected to the head-end controller through category 5 wires. The output of the pre-amplifier controller is connected to the multi-channel power amplifiers. The output of the amplifiers is connected to the remote speakers via speaker cables. The video signals from the controller are also amplified and sent to the rooms via coaxial cables. As much as half the power from the amplifier can be lost on the speaker cables before it gets to the rooms. It also has the potential for other degradations in the signal quality and increased noise for longer speaker cable runs. The video signals also suffer from similar signal attenuation. When the high frequencies of the video signals are attenuated, the picture appears soft and the details in the picture are lost. The attenuation of the amplitude of the video signal results in loss of brightness and contrast of the picture. Increase in video noise will result in a grainy picture with fuzziness and other video artifacts. Also one common problem is ground loops or hum bars on the video screen due to the long cable runs.
Figure 1
Besides the shortcomings on the audio and video performance of the traditional approach, it also has limitations on adding remote sources to the system, such as being able to share a DVD player from one of the bedrooms to the other areas of the house, or sending MP3 audio from a computer in the office to the head-end for distribution throughout the house. Obviously upgrading the system to distribute S-video or component video and Dolby Digital audio is impossible! The novel approach discussed next will demonstrate that with the use of technology, not only it is possible to have the best quality of audio and video but it can be expanded and upgraded in the future to support S-video, component video and Dolby Digital audio as well.
Design overview
The rapid growth in data communications and networking industry over the last two decades have led to the availability of very high performance and inexpensive category 5 twisted pair cables. The phenomenal growth and development in the semiconductors and integrated circuit technology has yielded very powerful audio and video signal processing circuits. These advances in technologies have culminated in the design of CATSTM (Complete Audio/Video Transmission System) based on a proprietary and patent pending BDSPTM technology for distribution of high quality audio/video signals over category 5 unshielded twisted pair cables.
A basic application to distribute multiple audio and video signals to multiple rooms in the house on category 5 wires is shown in Figure 2. In this example, again there are 5 audio/video zones and 5 audio only zones. The signals from sources such as DVD player, DSS receiver, CD carousel, etc. are connected to the CATS™ encoder/transmitter and put on the category 5 cables. The category 5 wires are connected to the central matrix router switcher, which then distributes all the signals to various rooms. The same category wires that carry the audio and video signals to the rooms also carry the Infra-Red remote or keypad data for control back to the central location. From the central location, all the rooms get a category 5 cable to the CATS™ decoder/receiver unit that is connected to the local video monitor and speakers. In the remote rooms, the user has a choice to view and control any of the 8 A/V sources available. The CATS™ employs distributed intelligence in its command and control execution. When local commands such as volume up, volume down and mute are issued in the room, they are executed locally in the room by the CATS™ receiver unit. When the IR remote control is pressed for a source selection such as the DVD or DSS, the signal travels back on the same category 5 cable to the central CATS™ router unit. The router interprets the data and switches the desired source to the room. Any source control command such as Play, Pause, Stop, Next track, etc. that is received from the room will be forwarded by the router to the source transmitter. An IR emitter connected to the CATS™ transmitter/encoder unit will flash the IR commands to the source equipment such as DSS or DVD player. Since there is a pre-amplifier built into the receiving CATS™ units, each room has the ability to set independent audio level. The audio and video quality of the signal in each room is exactly the same as the source equipment (DVD quality) without any degradation. It is as if the DVD or DSS was directly connected in each room.
Figure 2
A more elaborate set-up is shown in Figure 3 where all the sources are remotely located throughout the house. The only thing that is central is the CATS™ router which accepts the category 5 wires from various rooms. In this set-up a DVD player from the master bedroom is shared by other rooms in the house and the MP3 output from a computer is available for distribution.
Figure 3
This creates a true high-performance multi-source, multi-zone set up that can be expanded up to 8 sources and 8 zones on category 5 wires. In the future, the CATS™ equipment can be upgraded to provide S-video or component video and Dolby Digital distribution to every room on the same category 5 wires!
Conclusion
CATSTM represents a major breakthrough in high quality audio/video signal distribution and control on category 5 cables. It solves problems that have plagued traditional methods for over four decades. The superior signal quality level, the versatility of the system, and the complete avoidance of problems which plague traditional method, make CATSTM the best overall approach to multi-room video and distributed audio system on category 5 wires.
CATSTM has been successfully installed in numerous residential systems for multi-source multi-zone systems and a variety of commercial applications including enhanced video conferencing setups in corporate buildings, media retrieval systems in schools.
About the Company
Pragmatic Communications Systems, Inc., is a Silicon valley company established in 1994 to design, develop, and produce a variety of innovative products for wireless audio, video, and data communications. The majority of company’s products until 1997 were primarily designed for industrial and commercial applications. The success of these products has led to a strong and dynamic technology base, which has been applied to new generation of products such as CATSTM and others like the DMSTM, TrueMusicTM wireless hi-fi system and TrueViewTM wireless video system. The company’s philosophy is to use its technologies to solve problems that have gone unresolved for decades.
For more information:
Pragmatic
Communications Systems, Inc.
544
E. Weddell Drive, Unit 8
Sunnyvale,
CA 94089 USA
Tel.
(408) 542 0330
Fax
(408) 542 0339
Email: sales@wireless-experts.com
Web:
www.wireless-experts.com
Author’s biography
Prasanna M. Shah is the Chief Pragmatist and Thinker at Pragmatic Communications Systems, Inc. He earned his M.S. degree in Electrical Engineering from Stanford University and B.S. degree in Electrical Engineering from Santa Clara University, Santa Clara, CA. He has more than two decades of experience working on semiconductors for analog and digital audio, video, cellular telephones, wireless communications, fiber optic communications, data communications, data acquisition and industrial controls in the Silicon Valley. He holds one patent on power line communications and several patents pending on audio, video and wireless multimedia systems. An avid audiophile and music lover, in his free time, he likes to apply his pragmatic thinking to solve complex problems.
CATSTM, TrueViewTM, TrueMusicTM and DMSTM are trademarks of Pragmatic Communications Systems, Inc.
