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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: 618314" data-attributes="member: 10224"><p><strong>The Measured Parameters</strong></p><p>In an interconnection system, the cable's performance is important, but most important is the connector's performance, where one can suppose the signal degradation occurs, especially in live concert applications, where the extremely dynamic cable movement produced by the artists can generate a connection mechanical instability. For this reason, we linked the systems under test to the measurement instruments using the connectors complementary to those mounted by the manufacturer at the end of the cable, so the measured parameters refer to both the cable and the two connections. The obtained results will be pejorative, compared with those obtained testing only the cable, but they will reflect more realistic applications. </p><p> </p><p> </p><p>To characterize the interconnection systems, we measured their main parameters, such as the electrical R-L-C, the frequency response (magnitude and phase characteristics) and crosstalk, at different signal frequencies.</p><p> </p><p>The R-L-C parameters have been measured with the Wayne Kerr 4265 impedance meter at a frequency up to 100 kHz, with the connections shown in <strong>Figure 2</strong> and <strong>Figure 3</strong>. </p><p> </p><p>The transfer function has been measured by means of the Stanford DS345 function generator, the Keithley 2001 voltmeter, the HP 5335A counter and the LeCroy LC584AXL digital oscilloscope (<strong>Figure 4</strong>). Sinusoidal signals at different frequencies (from 10 Hz to 100 kHz) have been applied at the cable input, terminated with the generator characteristic impedance (50 Ω). The V1 and V2 signal amplitudes and the phase differences have been measured by means of the voltmeter and counter; visualizing the signals on the oscilloscope. The crosstalk has been measured according to , using a Stanford DS345 function generator and a Stanford SR770 FFT Signal Analyzer. A 2 Vrms sinusoidal signal (Vg) in the frequency range 10 Hz — 100 kHz has been applied to the driven line, terminated with the generator characteristic impedance (50 Ω). The coupled signal, induced on the quiet line (Vi) is measured with the spectrum analyzer.</p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure2.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 2:</strong> Resistance and inductance measurement</p><p> </p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure3.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 3:</strong> Capacitance measurement</p><p> </p><p><img src="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure4.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> </p><p><strong>Figure 4:</strong> Frequency response measurement</p><p> </p><p> </p><p>The quiet line is terminated with the analyzer characteristic impedance (50 Ω for the single-ended input and 100 Ω for the differential input). We measured two parameters:</p><p></p><ol> <li data-xf-list-type="ol">the NEXT (near end crosstalk ratio), the ratio of the signal amplitude measured at the line in proximity to the generator to the generated signal amplitude Vnext / Vg (<strong><a href="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure5.gif" target="_blank">Figure 5</a></strong>).</li> <li data-xf-list-type="ol">the FEXT (far end crosstalk ratio), the ratio of the signal amplitude measured at the far end of the quiet line to the generated signal amplitude Vfext / Vg (<strong><a href="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure6.gif" target="_blank">Figure 6</a></strong>).</li> </ol><p>The Measurement System</p><p>In order to guarantee the repeatability of lumped parameters and crosstalk ratio measurements, an automatic testing system has been adopted. The system architecture for the crosstalk measurement is shown in <strong>Figure 7</strong>. </p><p> </p><p> </p><p> </p><p> </p><p></p><p>A PC hosts an IEEE 488 board for the communication with: <ul> <li data-xf-list-type="ul">The Stanford DS 345 that generates the sinusoidal input signals at the different frequency values;</li> <li data-xf-list-type="ul">The Stanford 770SR FFT Network Spectrum Analyzer that performs the amplitude spectrum evaluation and measures the crosstalk signal amplitudes;</li> <li data-xf-list-type="ul">The Keythley 2001 multimeter that performs a high accuracy measurement of the input voltage amplitude to control the stability of the signals at the different frequency values.</li> </ul><p></p><p></p><p>The control and measurement software has been developed in the National Instruments LabVIEW environment. It has been developed to perform the following steps: <ol> <li data-xf-list-type="ol">the reset of all the apparatuses;</li> <li data-xf-list-type="ol">the setting of the function generator for the sinusoidal input signal generation;</li> <li data-xf-list-type="ol">the monitoring of the input signal amplitude;</li> <li data-xf-list-type="ol">the setting of the frequency, input configuration and measurement mode for the analyzer;</li> <li data-xf-list-type="ol">the synchronized running of the different instruments;</li> <li data-xf-list-type="ol">the acquisition of measured values from the spectrum analyzer and digital multimeter.</li> </ol><p>The crosstalk ratio measurements have been performed setting the function generator output at 2.000 Vrms. For the accurate measurement of the crosstalk voltage amplitude, the spectrum analyzer has been configured using suitable values of frequency span range, a differential input stage and a peak hold mode. The adopted center frequency and span values are tabulated in <strong>Table 1</strong>.</p></blockquote><p></p>
[QUOTE="vas silis, post: 618314, member: 10224"] [B]The Measured Parameters[/B] In an interconnection system, the cable's performance is important, but most important is the connector's performance, where one can suppose the signal degradation occurs, especially in live concert applications, where the extremely dynamic cable movement produced by the artists can generate a connection mechanical instability. For this reason, we linked the systems under test to the measurement instruments using the connectors complementary to those mounted by the manufacturer at the end of the cable, so the measured parameters refer to both the cable and the two connections. The obtained results will be pejorative, compared with those obtained testing only the cable, but they will reflect more realistic applications. To characterize the interconnection systems, we measured their main parameters, such as the electrical R-L-C, the frequency response (magnitude and phase characteristics) and crosstalk, at different signal frequencies. The R-L-C parameters have been measured with the Wayne Kerr 4265 impedance meter at a frequency up to 100 kHz, with the connections shown in [B]Figure 2[/B] and [B]Figure 3[/B]. The transfer function has been measured by means of the Stanford DS345 function generator, the Keithley 2001 voltmeter, the HP 5335A counter and the LeCroy LC584AXL digital oscilloscope ([B]Figure 4[/B]). Sinusoidal signals at different frequencies (from 10 Hz to 100 kHz) have been applied at the cable input, terminated with the generator characteristic impedance (50 Ω). The V1 and V2 signal amplitudes and the phase differences have been measured by means of the voltmeter and counter; visualizing the signals on the oscilloscope. The crosstalk has been measured according to , using a Stanford DS345 function generator and a Stanford SR770 FFT Signal Analyzer. A 2 Vrms sinusoidal signal (Vg) in the frequency range 10 Hz — 100 kHz has been applied to the driven line, terminated with the generator characteristic impedance (50 Ω). The coupled signal, induced on the quiet line (Vi) is measured with the spectrum analyzer. [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure2.gif[/IMG] [B]Figure 2:[/B] Resistance and inductance measurement [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure3.gif[/IMG] [B]Figure 3:[/B] Capacitance measurement [IMG]http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure4.gif[/IMG] [B]Figure 4:[/B] Frequency response measurement The quiet line is terminated with the analyzer characteristic impedance (50 Ω for the single-ended input and 100 Ω for the differential input). We measured two parameters: [LIST=1] [*]the NEXT (near end crosstalk ratio), the ratio of the signal amplitude measured at the line in proximity to the generator to the generated signal amplitude Vnext / Vg ([B][URL="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure5.gif"]Figure 5[/URL][/B]). [*]the FEXT (far end crosstalk ratio), the ratio of the signal amplitude measured at the far end of the quiet line to the generated signal amplitude Vfext / Vg ([B][URL="http://i.cmpnet.com/techonline/images/community/content/feature/fiorucci/figure6.gif"]Figure 6[/URL][/B]).[/LIST]The Measurement System In order to guarantee the repeatability of lumped parameters and crosstalk ratio measurements, an automatic testing system has been adopted. The system architecture for the crosstalk measurement is shown in [B]Figure 7[/B]. A PC hosts an IEEE 488 board for the communication with:[LIST] [*]The Stanford DS 345 that generates the sinusoidal input signals at the different frequency values; [*]The Stanford 770SR FFT Network Spectrum Analyzer that performs the amplitude spectrum evaluation and measures the crosstalk signal amplitudes; [*]The Keythley 2001 multimeter that performs a high accuracy measurement of the input voltage amplitude to control the stability of the signals at the different frequency values.[/LIST] The control and measurement software has been developed in the National Instruments LabVIEW environment. It has been developed to perform the following steps:[LIST=1] [*]the reset of all the apparatuses; [*]the setting of the function generator for the sinusoidal input signal generation; [*]the monitoring of the input signal amplitude; [*]the setting of the frequency, input configuration and measurement mode for the analyzer; [*]the synchronized running of the different instruments; [*]the acquisition of measured values from the spectrum analyzer and digital multimeter.[/LIST]The crosstalk ratio measurements have been performed setting the function generator output at 2.000 Vrms. For the accurate measurement of the crosstalk voltage amplitude, the spectrum analyzer has been configured using suitable values of frequency span range, a differential input stage and a peak hold mode. The adopted center frequency and span values are tabulated in [B]Table 1[/B]. [/QUOTE]
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Καλωδια, r l c - crosstalk κλπ.
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