Method for avoiding undesirable minima of the frequency, return loss (srl) of coaxial high-frequency cables

摘要

During the extrusion of the conductor insulation the density of the insulation is measured by means of radiation (UV or X-rays) in conjunction with electronic methods and registered. The density can then be automatically regulated to the desired value. The density may also be measured after extrusion before the next process stage. The measurement can be executed in a short distance after the extruder by one or two radiation sources placed into each others orthogonal planes with their opposite receivers (vidicons), picturing the cable. The measured values are fed to an analyser and control unit. The extruder is controllable or may be provided with a heater winding the current through which is regulated depending on the values obtained.