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Clipping is a form of distortion that limits a signal once it exceeds a threshold. Clipping may occur when a signal is recorded by a sensor that has constraints on the range of data it can measure, it can occur when a signal is digitized, or it can occur any other time an analog or digital signal is transformed, particularly in the presence of gain or overshoot and undershoot. Clipping may be described as hard, in cases where the signal is strictly limited at the threshold, producing a flat cutoff; or it may be described as soft, in cases where the clipped signal continues to follow the original at a reduced gain. Hard clipping results in many high frequency harmonics; soft clipping results in fewer higher order harmonics and intermodulation distortion components. ==Audio== (詳細はpower than its rated (sine wave) output when it is clipping. This extra power can damage any part of the loudspeaker, including the woofer, or the tweeter, by causing over-excursion, or by overheating the voice coil. It may cause damage to the amplifier's power supply or simply blow a fuse. In the frequency domain, clipping produces strong harmonics in the high frequency range (as the clipped waveform comes closer to a squarewave). The extra high frequency weighting of the signal could make tweeter damage more likely than if the signal was not clipped. However most loudspeakers are designed to handle signals like cymbal crashes that have even more high frequency weighting than amplifier clipping produces, so damage attributable to this characteristic is rare. Many electric guitar players intentionally overdrive their amplifiers (or insert a "fuzz box") to cause clipping in order to get a desired sound (see guitar distortion). Some audiophiles believe that the clipping behavior of vacuum tubes with little or no negative feedback is superior to that of transistors, in that vacuum tubes clip more gradually than transistors (i.e. ''soft'' clipping, and mostly even harmonics), resulting in harmonic distortion that is generally less objectionable. In general though, the distortion associated with clipping is unwanted, and is visible on an oscilloscope even if it is inaudible. Even in a transistorised amplifier with hard clipping, the gain of the transistor will be reducing (leading to nonlinear distortion) as the output current increases and the voltage across the transistor reduces close to the saturation voltage (for bipolar transistors), and so "full power" for the purposes of measuring distortion in amplifiers is usually taken as a few percent ''below'' clipping. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clipping (signal processing)」の詳細全文を読む スポンサード リンク
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