Journal of Electronic Systems Oleg Borisov Panagiev 11 4 2021 https://doi.org/10.6025/jes/2021/11/4/105-112 https://www.dline.info/jes/fulltext/v11n4/jesv11n4_1.pdf The authors have studied the oscillation frequencies in the modulators and channel converters in a Head End for cable TV. The standards used are channel 46 from the UHF range of B/G and the test channel is (n). The study of the work is the digital signals with a one-circular chain PLL and they are made from modules forming both analog and digital signals.