TV AND DATA CABLE SYSTEM INGRESS NOISE BLOCKER

摘要

This invention permits the upstream transmission of short packets of information in a cable TV system, and blocking upstream noise at all other times, and does so without interfering with image quality of normal TV viewing. A remotely operable ingress noise blocking filter (45) is placed at the terminating junction between a subscriber's coaxial drop cable (24) and a corresponding feeder tap (20) in a cable TV system. The ingress noise blocking filter (45) contains a high pass filter (47) to pass the normal TV band. This high pass filter is bypassed by a section (46) containing low pass filters (48) and a switch (50) operated when receiving a control signal from a cable modem during those short durations, the cable modem is authorized to transmit an upstream signal. Low pass filters (48) isolate the switching elements so that switching transients cannot occur in the downstream TV band.