Method for locating defective points in a high frequency (hf) signal transmission path

A method for locating points in a signal transmission path for a high frequency signal, said points being defective in terms of high frequency transmission characteristics of the signal transmission path, comprising the following steps:

• (a) generating of a first HF signal with a constant predetermined frequency f1 and a signal modulated by a predetermined type of modulation, wherein the type of modulation is an amplitude modulation or a digital modulation, and wherein the superimposed modulated signal is a noise;
• (b) generating a second HF signal with a constant predetermined frequency f2;.
• (c) generating a predetermined intermodulation product in the form of an intermodulation product signal with the frequency fIM-GENERATED from the first and the second HF signal;
• (d) introducing the first HF signal and of the second HF signal into the signal transmission path at a predetermined introduction point;
• (e) receiving, at the predetermined introduction point, of an intermodulation product which is generated in the signal transmission path from the first HF signal and the second HF signal at a defective point and reflected back to the introduction point and which corresponds to the intermodulation product generated in step (c), in the form of an intermodulation product signal having the frequency fIM-RECEIVED;
• (f) determining a time lag tx between the generated intermodulation product signal fIM-GENERATED and the received intermodulation product signal fIM-RECEIVED by a cross-correlation;
• and
• (g) calculating a length L between the introduction point and the point in the signal transmission path from which the signal received in step (e) has been reflected, from the time lag tx determined in step (f).