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Hi-End
Hi-End καλώδια και αξεσουάρ
Καλωδια, r l c - crosstalk κλπ.
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<blockquote data-quote="vas silis" data-source="post: 618324" data-attributes="member: 10224"><p><span style="color: #ffffff"><strong>Center Frequency</strong></span><span style="color: #ffffff"><strong>Span</strong></span></p><p>10 97.5 Hz</p><p>20 390 Hz</p><p>50 780 Hz</p><p>100 780 Hz</p><p>200 780 Hz</p><p>500 780 Hz</p><p>1,000 780 Hz</p><p>2,000 780 Hz</p><p>5,000 780 Hz</p><p>10,000 780 Hz</p><p>20,000 780 Hz</p><p>30,000 780 Hz</p><p>40,000 780 Hz</p><p>50,000 780 Hz</p><p>100,000 1.56 kHz</p><p> </p><p> </p><p> </p><p><strong>Table 1:</strong> Frequency and span for crosstalk measurements.</p><p> </p><p> </p><p>The multimeter has been configured to operate in high resolution mode, averaging 100 measures. We carried out the measurements on sale-ready cables, with length ranging from 5 to 10 meters. This choice has involved some problems due to their very low values of the lumped parameters. Specifically, a very critical aspect is the contact resistance compensation, because of the reduced resistances that the tested cables have shown. To obtain satisfactorily results, we performed the instrument calibration procedure at each measurement frequency.</p><p> </p><p>The crosstalk voltage measurement is critical; specifically, the measured rms voltage values are in the range 20 µV - 100 mV. The adoption of the differential voltage measurement helps to reduce the noise effect; however, for each frequency value we also performed the voltage measurement without the input signals, to evaluate the noise level. The characterization of the multipolar cables requires the crosstalk measurements on a high number of conductors with the respective shield.</p><p> </p><p>The mutual position and the distance between the driven line and the quiet line can introduce many relevant effects in the measurement crosstalk parameters. We measured the NEXT and FEXT swapping the driven and quiet lines, to evaluate the crosstalk symmetry.</p><p> </p><p>We tested a set of conductor couples in different mutual positions from the centre to the border of the cable.</p><p> </p><p> </p><p>The experimental results</p><p>The described measurement procedures have been adopted for the characterization of 20 PROEL cables, constructed using high purity oxygen-free copper (OFC): i) professional flexible musical instrument cables (with and without connectors for evaluating the effect of the connectors on the signal transmission); ii) professional flexible passive speaker cables OFC red copper conductors; iii) professional flexible microphone cables OFC red copper conductors. </p><p> </p><p> </p><p>As an example of the obtained results, the diagrams in <strong>Figure 7</strong> through <strong>Figure 17</strong> show the lumped elements, frequency response (amplitude and phase) and crosstalk characteristics of three cables: the Die-hard DH340LU5, the HPC640BK (4 x 2.50 mm2) and the CMN20.</p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure7.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 7:</strong> Resistance from the beginning to the end of the white signal conductor [DH340LU5]</p><p> </p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure8.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 8:</strong> Inductance from the beginning to the end of the white signal conductor [DH340LU5]</p><p> </p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure9.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 9:</strong> Frequency response: amplitude characteristic measured from the conductor (white) and the conductor (blue) [HPC640BK]</p><p> </p><p> </p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure10.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 10:</strong> Frequency response: phase characteristic measured from the conductor (white) and the conductor (blue) [HPC640BK]</p></blockquote><p></p>
[QUOTE="vas silis, post: 618324, member: 10224"] [COLOR=#ffffff][B]Center Frequency[/B][/COLOR][COLOR=#ffffff][B]Span[/B][/COLOR] 10 97.5 Hz 20 390 Hz 50 780 Hz 100 780 Hz 200 780 Hz 500 780 Hz 1,000 780 Hz 2,000 780 Hz 5,000 780 Hz 10,000 780 Hz 20,000 780 Hz 30,000 780 Hz 40,000 780 Hz 50,000 780 Hz 100,000 1.56 kHz [B]Table 1:[/B] Frequency and span for crosstalk measurements. The multimeter has been configured to operate in high resolution mode, averaging 100 measures. We carried out the measurements on sale-ready cables, with length ranging from 5 to 10 meters. This choice has involved some problems due to their very low values of the lumped parameters. Specifically, a very critical aspect is the contact resistance compensation, because of the reduced resistances that the tested cables have shown. To obtain satisfactorily results, we performed the instrument calibration procedure at each measurement frequency. The crosstalk voltage measurement is critical; specifically, the measured rms voltage values are in the range 20 µV - 100 mV. The adoption of the differential voltage measurement helps to reduce the noise effect; however, for each frequency value we also performed the voltage measurement without the input signals, to evaluate the noise level. The characterization of the multipolar cables requires the crosstalk measurements on a high number of conductors with the respective shield. The mutual position and the distance between the driven line and the quiet line can introduce many relevant effects in the measurement crosstalk parameters. We measured the NEXT and FEXT swapping the driven and quiet lines, to evaluate the crosstalk symmetry. We tested a set of conductor couples in different mutual positions from the centre to the border of the cable. The experimental results The described measurement procedures have been adopted for the characterization of 20 PROEL cables, constructed using high purity oxygen-free copper (OFC): i) professional flexible musical instrument cables (with and without connectors for evaluating the effect of the connectors on the signal transmission); ii) professional flexible passive speaker cables OFC red copper conductors; iii) professional flexible microphone cables OFC red copper conductors. As an example of the obtained results, the diagrams in [B]Figure 7[/B] through [B]Figure 17[/B] show the lumped elements, frequency response (amplitude and phase) and crosstalk characteristics of three cables: the Die-hard DH340LU5, the HPC640BK (4 x 2.50 mm2) and the CMN20. [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure7.gif[/IMG] [B]Figure 7:[/B] Resistance from the beginning to the end of the white signal conductor [DH340LU5] [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure8.gif[/IMG] [B]Figure 8:[/B] Inductance from the beginning to the end of the white signal conductor [DH340LU5] [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure9.gif[/IMG] [B]Figure 9:[/B] Frequency response: amplitude characteristic measured from the conductor (white) and the conductor (blue) [HPC640BK] [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure10.gif[/IMG] [B]Figure 10:[/B] Frequency response: phase characteristic measured from the conductor (white) and the conductor (blue) [HPC640BK] [/QUOTE]
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Καλωδια, r l c - crosstalk κλπ.
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