Product category:
Analogue and Mixed Signal ICs
News Release from: National Semiconductor | Subject: LMH1251
Edited by the Electronicstalk Editorial
Team on 31 August 2005
All-in-one decoder takes analogue route
to RGB
A novel decoder with an integrated 2:1 multiplexing video switch uses analogue technology to accurately convert standard and high-definition video signals to a computer video format.
National Semiconductor has introduced the industry's first decoder with an integrated 2:1 multiplexing (mux) video switch that uses analogue technology to accurately convert standard and high-definition video (YPbPr) signals to a computer video (RGB) format The LMH1251 increases compatibility between different video standards and formats, allowing consumers to output video directly from DVD players, gaming devices and other devices to their personal computer monitors
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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The LMH1251 also performs all the necessary sync processing to generate horizontal and vertical sync signals from standard (SD) and high-definition (HD) video formats.
At IBC 2005 in Amsterdam, from 9th to 13th September, National will demonstrate the unique multimedia features and accurate colour space decoding of the LMH1251 in Hall 5, Stand 330 of the RAI Centre.
"Converting signals in the analogue domain through National's integrated, all-in-one decoder gets rid of all the complex external circuitry or additional chips you'd find in a digital solution", said Erroll Dietz, Vice President of National Semiconductor's Amplifier products group.
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"Instead, it offers manufacturers an easy way to add component video compatibility without the headaches and errors of current solutions".
"The LMH1251 demonstrates National's ability to provide advanced video solutions".
The LMH1251's conversion process is done using analogue technology via a colour-space conversion matrix, eliminating multiple stages of digital implementations.
The result is a cleaner, crisper, decoded video image that is superior to alternative approaches that use discrete components, digital products or field-programmable gate arrays (FPGAs).
Discrete solutions using up to 20 components require design expertise, use more board space, consume more power and have inferior decoding quality.
Digital solutions and FPGAs are more expensive and typically offer more features than may be needed in a system.
compared with these alternatives, the analogue design of the LMH1251 reduces undesired artifacts and provides a smaller form factor for easy integration.
National's LMH1251 converts video to within 1% accuracy based on vector scope analysis, which exceeds the accuracy of current solutions on the market.
The device accepts one set of YPbPr inputs and one set of RGB/Hsync/Vsync inputs.
Using the integrated 2:1 mux and based on the input selected, the output will be either a decoded TV or buffered PC video signal.
The LMH1251's RGB path has 400MHz of bandwidth, enabling it to accept up to 1600 x 1200 UXGA video resolutions.
The output displays the unaltered RGB video signal.
The YPbPr video path has 70MHz of bandwidth.
It is equipped with a smart video detection circuit that automatically senses 480i, 480p, 720p, 1080i and 1080p video formats, applying the appropriate colour-space conversion and outputting the video in a RGBHV format.
The LMH1251 eliminates the need for a microcontroller to choose the proper detection scheme and also saves board space by integrating all the necessary components: a sync processor, a 2:1 mux and an analogue colour-space conversion matrix.
Available now in a TSSOP-24 package, the LMH1251 is priced at $3.49 in 1000-unit quantities.
Lead-free package options are also available.
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