Creating integrated circuits that can generate chaotic signals

Researchers at Tokyo Institute of Technology have found a simple, yet highly versatile way to generate "chaotic signals" with various features. The technique consists of interconnecting three ring oscillators, effectively ...

Ultra-high-contrast digital sensing

Virtually any modern information-capture device—such as a camera, audio recorder, or telephone—has an analog-to-digital converter in it, a circuit that converts the fluctuating voltages of analog signals into strings ...

RedEye could let your phone see 24-7

Rice University researchers have just the thing for the age of information overload: an app that sees all and remembers only what it should.

World record silicon-based millimeter-wave power amplifiers

Two teams of DARPA performers have achieved world record power output levels using silicon-based technologies for millimeter-wave power amplifiers. RF power amplifiers are used in communications and sensor systems to boost ...

Shifting the Internet into high gear

( —A new-generation analog-to-digital converter (ADC) developed by a joint IBM-EPFL team has the potential to greatly increase the speed and volume of data that can be transferred over the Internet.

Wireless low-power active-electrode EEG headset presented

Imec, Holst Centre and Panasonic have developed a new prototype of a wireless EEG (electroencephalogram) headset. The system combines ease-of-use with ultra-low power electronics. Continuous impedance monitoring and the use ...

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Analog signal

An Analog or analogue signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e analogous to another time varying signal. It differs from a digital signal in that small fluctuations in the signal are meaningful. Analog is usually thought of in an electrical context; however, mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.

An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. Electrically, the property most commonly used is voltage followed closely by frequency, current, and charge.

Any information may be conveyed by an analog signal; often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure, and is achieved using a transducer.

For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which causes corresponding fluctuations in a voltage or the current in an electric circuit. The voltage or the current is said to be an "analog" of the sound.

Any measured analog signal must theoretically have noise and a finite slew rate. Therefore, both analog and digital systems are subject to limitations in resolution and bandwidth. In practice, as analog systems become more complex, effects such as non-linearity and noise ultimately degrade analog resolution to such extent that the performance of digital systems may surpass it. In analog systems, it is difficult to detect when such degradation occurs. However, in digital systems, degradation can not only be detected but corrected as well.

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