A method for the measurement of humming in cable television systems, during their operation

摘要

in a method for measuring of hum and low frequency distortion for the operation of the video signal kabelfernsehkanu00e4le modulated carrier frequency are spitzenabtastwerte of horizontal synchronsignals is given and the frequency of the vertical interval. ungsvoll at.the spitzenabtastwerte educated record is filtered and input to a fast fourier transformation, to size value of the components of basisfrequenz and first harmonic frequency, to obtain a power line conditions.from these gru00f6u00dfenwerten will hum and the low-frequency distortion as a percentage relative to the amplitude of the carrier frequency is calculated.the same procedure with an input signal at a mean measurement outside the firm, only the brummens are used, with the difference between the measurements in each company and outside the company, the low frequency distortion due to the videos ignals.