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In electronics, crosstalk is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, inductive, or conductive coupling from one circuit, part of a circuit, or channel, to another. ==In cabling== In structured cabling, crosstalk can refer to electromagnetic interference from one unshielded twisted pair to another twisted pair, normally running in parallel. ;Near end crosstalk (NEXT): NEXT is a measure of the ability of cabling to reject crosstalk. Interference between two pairs in a cable is measured at the same end of the cable as the interfering transmitter. Crosstalk is undesirable. In crosstalk, the signals traveling through adjacent pairs of wire in twisted-pair cabling interfere with each other. The pair causing the interference is called the “disturbing pair,” while the pair experiencing the interference is the “disturbed pair.” Channel NEXT is the NEXT value measured between one wire pair and another in the same cable; NEXT is measured at both ends of the wire. The NEXT value for a given cable type is generally expressed in decibels per feet or decibels per 1000 feet. NEXT value varies with the frequency of transmission. The higher the NEXT value, the greater the cable’s ability to reject crosstalk at its local connection. Generally specifications for cabling (such as CAT 5) include the minimum NEXT values.〔(【引用サイトリンク】title=Category 5 / 5E & Cat 6 Cabling Tutorial and FAQ's )〕 ;Power sum near end crosstalk (PSNEXT): PSNEXT is a NEXT measurement which includes the sum of crosstalk contributions of all adjacent pairs.〔 ;Far end crosstalk (FEXT): Interference between two pairs of a cable measured at the other end of the cable with respect to the interfering transmitter.〔 ;Equal level far end crosstalk (ELFEXT): An FEXT measurement with attenuation compensation.〔 ; (AXT): Interference caused by other cables routed close to the cable of interest. 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「Crosstalk」の詳細全文を読む スポンサード リンク
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