Capacitance measurement and analysis for a lossless data transmission
The lossless transmission of high frequency, analog or digital signals is an essential quality feature for LAN, coaxial or HF cables. The measurement of capacitance already during cable manufacturing plays an important role. The capacitance influences the wave impedance of the wire for the specified frequency area and therefore, the quality of cables.
For capacitance measurement, SIKORA offers the CAPACITANCE 2000. It is installed in the cooling trough and measures the capacitance of wire insulation during production. Simultaneously, the system determines capacitance changes and provides an extremely fast measuring value update and detects bare patches. This is realized by the combination of a short and a long measuring electrode (multi-zone technology), which are integrated within a measuring tube. The short measuring electrode determines periodical capacitance variations with high spatial resolution by means of a Fast Fourier Transformation (FFT). From the FFT data the Structural Return Loss (SRL) is determined and offers information about the expected attenuation of the HF signal during data transmission.
The long measuring electrode measures the average value of the capacitance. The prevention of the cable’s periodical variations is a prerequisite for optimal attenuation behavior, whereby the critical period interval becomes all the shorter the higher the aspired data transmission rate increases. These periodical variations are determined by the multi-zone technology of the CAPACITANCE 2000 as all parameters influencing the quality (e.g. conductor diameter, foaming, outer diameter) are mirrored in the capacitance.
The detection of periodical capacity variations as well as the prediction of the return loss (FFT and SRL) are available as special features directly at the measuring tube by means of a diagnosis interface. For a clear display of measuring values, SIKORA offers the REMOTE 2000. For a graphical processing, display of statistics, trends as well as recording, the processor devices of the ECOCONTROL Series are suitable.