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Adaptive noise cancelling is a signal processing technique that is highly effective in suppressing additive interference or noise corrupting a received target signal at the main or primary sensor in certain common situations where the interference is known and is accessible but unavoidable and where the target signal and the interference are unrelated, that is, uncorrelated [1] [2] [3].
Electronic noise management test in Vienna, 1973. The first patent for a noise control system— U.S. patent 2,043,416 —was granted to inventor Paul Lueg in 1936. The patent described how to cancel sinusoidal tones in ducts by phase-advancing the wave and canceling arbitrary sounds in the region around a loudspeaker by inverting the polarity. [3]
The cost, size, and complexity of the SIC solution is primarily determined by the analog stage. Also essential are the tuning algorithms that enable the canceller to adapt to rapid changes. Cancellation algorithms typically need to adapt at the rate of once every few hundred microseconds to keep up with changes in the environment. [3] [4]
The internal electronic circuitry of an active noise-canceling mic attempts to subtract noise signal from the primary microphone. The circuit may employ passive or active noise canceling techniques to filter out the noise, producing an output signal that has a lower noise floor and a higher signal-to-noise ratio .
Adaptive feedback cancellation originated during the evolution of the hearing aid. The hearing aid became digital, and as such feedback cancellation was needed. In 1980 a directional microphone was introduced in the digital hearing aid, and adaptive feedback cancellation was created to block external noise that the microphone picked up. Today ...
Test bench for active vibration control at the Fraunhofer Institute LBF. A piezo driven active engine mount cancels the vibration resulting from several motors on top of the Mount by inducing countervibrations. Active vibration control is the active application of force in an equal and opposite fashion to the forces imposed by external ...
The sudden absence of background noise gives the near-end user the impression that the line has gone dead. In response to this, Bell Labs developed echo canceler theory in the early 1960s, [4] [5] which then resulted in laboratory echo cancelers in the late 1960s and commercial echo cancelers in the 1980s. [6]
Analysis of sound and acoustics plays a role in such engineering tasks as product design, production test, machine performance, and process control. For instance, product design can require modification of sound level or noise for compliance with standards from ANSI, IEC, and ISO. The work might also involve design fine-tuning to meet market ...