Channelised gain control of line amplifiers

A line amplifier gain control system, comprising:

• a cable;
• an amplifier on said cable;
• a pilot signal generator for generating a pulsed pilot signal on an unused channel frequency;
• headend equipment for feeding signals into said cable, said headend equipment combining said pilot signal and voice channels into a combined signal, and feeding said combined signal into said cable;
• and
• a controller for determining a pilot signal output strength by measuring signal strength of said pilot signal after amplification by said amplifier, comparing the pilot signal output strength with a target signal strength to determine a difference, and adjusting the gain of said amplifier corresponding to said difference.

A line amplifier comprising:

• a downlink amplifier adapted to receive a composite signal, said composite signal comprising at least one voice channel and a pulsed pilot signal, said pilot signal comprising a target signal level, and said downlink amplifier amplifying said composite signal into an amplified signal;
• a sampler to determine an output level of said pilot signal in said amplified signal;
• a filter to extract said target signal level from said composite signal;
• and
• a processor to compare said target signal level and said output level, and adjust gain control of said downlink amplifier corresponding to a difference between said target signal level and said output level.