Method and device for disturbance suppression in a signal

A method for suppressing disturbances in signals transmitted on a transmission line, the method which comprises:

• receiving signals having an amplitude;
• adjusting the amplitude of the signals with coarse adjustment steps and with fine adjustment steps for a disturbance suppression, including:
• performing the coarse adjustment steps with a group delay filter selectively operating with a first filter stage suited for signals received from a transmission line having a first length and operating with a second filter stage suited for signals received from a transmission line having a second length, the second length being greater than the first length;
• and
• performing the fine adjustment steps with a gain control device selectively operating at a plurality of different gains, the fine adjustment steps covering a first amplitude range, when the group delay filter operates with the first filter stage and covering a second amplitude range when the filter operates with the second filter stage, the first amplitude range being greater than the second amplitude range;
• subsequently comparing the amplitude adjusted signals to at least a lower reference level and an upper reference level for determining a first percentage of the amplitude adjusted signals violating the lower reference level and a second percentage of the amplitude adjusted signals violating the upper reference level;
• selecting the coarse adjustment steps and the fine adjustment steps in accordance with an adjustment characteristic which evaluates at least the first percentage and the second percentage;
• changing the adjustment characteristic if a tendency of reference level violation of the amplitude adjusted signals is detected;
• and
• checking if the step of changing the adjustment characteristic improves the disturbance suppression.