A modern Audio-Video amplifier/receiver (AVR) is an exceedingly complex piece of consumer electronics, requiring expertise in many aspects of analogue and digital audio and high definition video, plus considerable software skills. ‘The anatomy of a modern audio-video amplifier’ lecture by John Dawson from Arcam for Audio Engineering Society UK is an interesting talk on engineering →
An instrumentation amplifier is a type of differential amplifier that has been outfitted with input buffers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment. The ideal common-mode gain of an instrumentation amplifier is zero, which means that it is a very →
Ground loops affect video signals. Understand them, then deal with them. When designing or installing the cables for a video transmission system, one assumption that engineers commonly make is that the local earth grounds of both ends of the cable are the same. When circumstances don’t support this assumption, the video performance can exhibit gross →
An EE’s Guide to Survival Between Microphone and Voice Coil is an interesting slide set amde by Netherlands´ well known audio engineer Bruno Putzeys and put to web by Hypex Electronics and Grimm Audio. It was presented in AES convention at 2007. It is a very good presentation of the whole audio electronics path from →
Use right ground symbol in your electronics schematics and other drawings. Earth-ground symbol represents a real connection to earth. That connection could be for example 10-foot-high copper-clad steel bar driven into the earth (at your premises or nearby provided by power company) or metal water lines. That earth ground is wired to the neutral of →
Ground loops are a common problem in many experimental setups. A ground loop is an un- wanted closed loop of cables in the setup, most often through the ground system. Those ground loops are often hard to find and debug. A Ground Loop Detector document describes how to build and test a simple system to →
Remember that a real life return path for current is not an ocean of zero impedance. Some engineers draw every ground as a wire because even copper planes have impendance. This approach might be one reason that makes some audio engineers more think of using single-point grounding. By discarding ground planes in favor of thin →
Ground loop elimination in video systems does not always ask for a complete isolation of the grounds. There are passive hum suppressor transformers that will very effectively remove the hum from the video signal, but do not affect the video signal otherwise. Those special transformers act like a common mode coils, which stop the annoying →
RC filter or amplifier’s lowpass filter at the input of a delta-sigma ADC is normally put there to reduce noise. But sometimes adding a filter can produce a noisier digital output than without that filter. Using an analog filter to inject noise article tells that it is as easy to eliminate higher-frequency noise with an →
Researches are developing a new generation of contact lenses built with very small circuits and LEDs. They promises bionic eyesight in the future. Bionanotechnology researcher Babak A Parviz writes about his research toward producing a computer interface in a contact lens at IEEE Spectrum article Augmented Reality in a Contact Lens. The author states that, →