The English translation of high-speed cable is Direct Attach Cable, or DAC for short. This article will introduce several key factors that affect the transmission performance of DAC high-speed cable.
1. Cable attenuation
Cable attenuation refers to the reduction or loss of signal energy that occurs during the transmission of information to the device through the cable. During the transmission of high-speed cables, as the frequency increases, the attenuation will increase. In addition to the increase in frequency attenuation, temperature will also increase the attenuation of the cable. For every 10°C increase in temperature, the signal attenuation of the cable will increase by 4%.
2. Cable crosstalk
Crosstalk is also an important factor affecting cable performance. Crosstalk is a harmful interference signal, which comes from the coupling effect between pairs. This type of noise will cause random changes in signal amplitude, which will limit the receiver’s ability to monitor changes in signal waveforms, thereby affecting the bit error rate and reliability of the transmitted signal.
3. The cable is excessively bent
Cable bending will weaken the transmission signal, the cable is easy to bend, and the recovery ability after bending is relatively poor. In addition, the cable insulation part is a foamed structure, which has poor mechanical properties and is easily squeezed or stretched. It will be deformed to damage the foam layer structure. Therefore, in the process of using high-speed cables, we should try our best to avoid twisting and bending the insulated core wire, which will cause the conductor to bend and affect the performance.
4. Wiring environment
The operating environment will also affect the performance and service life of high-speed cables. Factors such as high temperature, ultraviolet radiation, and too much humidity will affect the transmission performance of high-speed cables. Therefore, when we lay out cables outdoors, we should lay them out under the eaves. In a place protected from light, moisture, and shade.
5. Electromagnetic and radio frequency interference
Copper cables are most afraid of EMI/RFI (electromagnetic interference/radio frequency interference) during application. Although high-speed cables are generally resistant to electromagnetic/radio frequency interference, we should also avoid potential Source of interference.
Correct grounding is the key to effective shielding. Failure to ground or incorrect grounding may reduce the effectiveness of the shielding. The ideal shield grounding should have only a single contact. When the interference signal is coupled to the shielding layer, the current will be led to the ground, avoiding the influence of the wire pairs under the shielding layer.