The Effect of Ingress Noise on a Digital Signal Transmission in the Two-way CATV System Using UHF Upstream Band

In this paper, it is shown that upstream digital signals are affected by the ingress noise in the upstream band of a two-way CATV system. The carrier-to-noise ratio of the digital data signal may be reflected by the immunity characteristics of each subscriber's unit, which consists of a CATV protector connected to a coaxial cable. It was found by bit-error-rate measurement in the two-way CATV model system that the value of the relative operating level is smaller in the UHF upstream band than the value in the HF to VHF one.