I had been getting some intermittent noise from my Panasonic PT-AE900E video projector after some years of usage. It sounded like a dry bearing on a fan, but it turned out that it was iris that caused the problem. I decided to take a more look at this problems when I had time to change →
I just accidentally found my way to Super cool video hack: DIY Olympics virtual lane markers page that looked interesting. It says that a student, Xiaoyang Kao, recently figured out how to make his own Olympics-style lane markers. The virtual lane graphics for swimming with css3 page tells how this video effect was done. Instead →
I wrote few years ago blog article Unshielded RCA cable is bad design. I just received yesterday a comment on it: “It’s not always that simple. There are equipment combinations which REQUIRE twisted pair RCA. Here’s explanation: http://www.youtube.com/watch?v=QOagVDZLQnA” So I watched this Truth about RCA signal cables video mentioned on this comment: The video was →
Google called the MPEG-LA’s bluff, and won article has one interesting point on H.264 to think about: those H.264 licenses embedded in Windows, OS X, iOS, your ‘professional’ camera, and so on, do not cover commercial use. This means according to article that if you shoot a video with your camera in H.264, upload it →
In my Audio and video signal susceptibility classes I wrote that digital video interfaces like DVI and HDMI can also have ground loop noise problems as they use a combination of balanced and unbalanced signals. Ground loop problem is one very possible source of intermittent problems over long distance in HDMI installations. This article is →
HDMI uses copy protection system called HDCP. And I have know for some years that HDMI copy protection broken. But based on recent information that has popped out it seems that it is even more broken that I thought that it was. Hackaday tells that HDMI breakout lets you sniff HDCP crypto keys and points →
Here are some pointers to useful audio electronics design articles that touch grounding and shielding issues: Grounding and Shielding Audio Devices Grounding The Circuit Designer’s Companion →
Balanced inputs and outputs have been used for many years in professional audio, but profound misconceptions about their operation and effectiveness still survive. Conventional wisdom about them is sometimes wrong. Balanced Line Technology web page gives you a good look at the balanced line technology in audio applications. The balanced line technology is also applicable →
My article Signal reference grids in the data center shows that different types of data communication interfaces are classified into susceptibility classes: Data communication interface classification Susceptibility class: Low immunity Interfaces in class: Parallel ports, RS-232 ports, Proprietary back-plane, Video cables Characteristics: Copper cabling with ground referenced signals. Any shift in ground voltage between the →
One of the most common direct coupled noise sources is when the ground which is being used for reference or return is not referenced to earth as expected. This is especially prevalent in sensitive high-gain circuits. Grounding and Shielding Existing Equipment – How to effectively minimize EMI issues when best practices are not available is →