Depth transducer system for a seismic streamer cable

A depth transducer system for ship-towed seismic marine streamer cable comprising:

• a plurality of depth transducers externally secured to a seismic streamer cable at successively greater distances from a towing ship;
• means for periodically transmitting an electrical control signal through a common transmission line mounted internally of said streamer cable;
• external inductive pickups partially embracing said streamer cable, associated with said depth transducers, for sensing the presence of a control signal in said common transmission line;
• means for delaying the dispatch of the depth-proportional signal in known relationship to the distances of the respective depth transducers from the towing ship;
• and
• means in said depth transducers responsive to a control signal sensed by said inductive pickups for dispatching a depth-proportional signal to said inductive pickups for transmission through said common transmission line.

A depth transducer system for a ship-towed seismic streamer cable, comprising:

• a common transmission line in said streamer cable;
• a plurality of depth transducers externally mounted at intervals along said streamer cable and inductively coupled to said transmission line;
• means for dispatching a control signal through said common transmission line;
• means in the respective depth transducers for receiving said control signal in timed sequence and in response thereto for launching a depth-proportional signal into said common transmission line.