System equalization for repeatered submarine cable system

Claim 1

A system equalizer, for use in a repeatered submarine cable system including automatic gain controlled submerged of a temperature following type, comprising: a switchable equalizer connected to a repeatered submarine cable system including automatic gain controlled submerged repeaters of a temperature following type and switchable to select an optimum one of a plurality of loss-frequency characteristics corresponding to the total of compensation errors in said automatic gain controlled submerged repeaters to compensate for a seasonal misalignment of the repeatered cable system; an automatic equalizer, including pilot signal detecting means for detecting a pilot signal transmitted through the repeatered cable system and for developing a control signal representative of the detected pilot signal, and connected to said switchable equalizer and having a loss-frequency characteristic proportional to the square root of frequency to compensate for short-term level fluctuations of the repeatered cable system under control of the control signal developed by said pilot signal detecting means; and an adjustable equalizer connected to said automatic equalizer to compensate for an unknown fixed deviation developed at an output of said automatic equalizer.

Claim 2

A system equalizer, for use in a repeatered submarine cable system including automatic gain controlled submerged of a temperature following type, comprising: a switchable equalizer connected to a repeatered submarine cable system including automatic gain controlled submerged repeaters of a temperature following type and switchable to select an optimum one of a plurality of loss-frequency characteristics corresponding to the total of compensation errors in said automatic gain controlled submerged repeaters to compensate for a seasonal misalignment of the repeatered cable system; an automatic equalizer, including pilot signal detecting means for detecting a pilot signal transmitted through the repeatered cable system and for developing a control signal representative of the detected pilot signal, and connected to said switchable equalizer and having a loss-frequency characteristic proportional to the square root of frequency to compensate for short-term level fluctuations of the repeatered cable system under control of the control signal developed by said pilot signal detecting means; and an adjustable equalizer connected to said automatic equalizer to compensate for an unknown fixed deviation developed at an output of said automatic equalizer.

Claim 7

A method for equalizing the loss-frequency characteristic of a repeatered submarine cable system including automatic gain controlled submerged repeaters of a temperature follow type, and a switchable equalizer comprising: measuring frequencies of repeater-supervisory tone signals from oscillators of the repeaters for detecting the operation temperatures of corresponding repeater sections; switching the switchable equalizer connected to said repeatered submarine cable system and to select an optimum one of a plurality of loss-frequency characteristics corresponding to the total of compensation errors in the automatic gain controlled submerged repeaters in consideration of the above detected operation temperatures to compensate for the seasonal misalignment of said repeatered cable system; connecting to the output of said switchable equalizer an automatic equalizer having a loss-frequency characteristic proportional to the square root of frequency to compensate for short-term level fluctuations of the repeatered cable system and which includes detection means for detecting a pilot signal transmitted through said repeatered submarine cabel system to control the compensation of the short-term level fluctuations; adjusting the level of said pilot signal at the input of said detection means to compensate for a total of misalignment deviations of the respective repeater sections; and connecting an adjustable equalizer to the output of said automatic equalizer to compensate for an unknown fixed deviation at the output of said automatic equalizer.

Claim 8

A method for equalizing the loss-frequency characteristic of a repeatered submarine cable system including automatic gain controlled submerged repeaters of a temperature follow type, and a switchable equalizer comprising: measuring frequencies of repeater-supervisory tone signals from oscillators of the repeaters for detecting the operation temperatures of corresponding repeater sections; switching the switchable equalizer connected to said repeatered submarine cable system and to select an optimum one of a plurality of loss-frequency characteristics corresponding to the total of compensation errors in the automatic gain controlled submerged repeaters in consideration of the above detected operation temperatures to compensate for the seasonal misalignment of said repeatered cable system; connecting to the output of said switchable equalizer an automatic equalizer having a loss-frequency characteristic proportional to the square root of frequency to compensate for short-term level fluctuations of the repeatered cable system and which includes detection means for detecting a pilot signal transmitted through said repeatered submarine cabel system to control the compensation of the short-term level fluctuations; adjusting the level of said pilot signal at the input of said detection means to compensate for a total of misalignment deviations of the respective repeater sections; and connecting an adjustable equalizer to the output of said automatic equalizer to compensate for an unknown fixed deviation at the output of said automatic equalizer.