Telemetry data transmission circuit having selectable clock source

A method of synchronizing an operation of a telemetry data transmission circuit in a towed hydrophone streamer comprised of a first module and a second module, said first module and said second module interchangeable within said streamer, comprising the steps of:

• receiving a master timing signal from a master clock source located in said first module into a slave dock input in said second module, said master timing signal capable of synchronizing said operation of said transmission circuit to allow said transmission circuit to place telemetry data from said second module on a data bus coupled to said transmission circuit and running a length of said streamer;
• receiving a local timing signal from a local clock source located in said second module into a local clock input in said second module, said local timing signal alternatively capable of synchronizing said operation of said transmission circuit;
• and
• allowing said local clock source to synchronize said operation of said transmission circuit as a function of a condition of said master timing signal with a clock source selection circuit.

A towed acoustic streamer, comprising:

• a plurality of interchangeable modules connected in series, each of said modules containing a plurality of hydrophones and a data bus running a length of said each of said modules, said data bus coupled to recording equipment onboard a towing vessel, said towing vessel coupled to a forward end of said streamer, each of said modules further containing a telemetry data transmission circuit including:
• a slave clock input capable of receiving a master timing signal from a master clock source located in another module, said master timing signal capable of synchronizing an operation of said transmission circuit to allow said transmission circuit to place local telemetry data from said plurality of hydrophones on said data bus;
• a local clock input capable of receiving a local timing signal from a local clock source, said local timing signal alternatively capable of synchronizing said operation of said transmission circuit;
• and
• a clock source selection circuit capable of allowing said local clock source to synchronize said operation of said transmission circuit as a function of a condition of said master timing signal,
• said each of said modules receiving said master clock signal from an aftmost functioning module, said clock selection circuit allowing a module forward of said aftmost module to generate said master clock signal when said aftmost module is faulty.