Abstract: Apparatus comprising a frame disposable in spaced relationship about a pipe uses a ring mounted thereon for carrying a welding head around the pipe. A welding torch is provided on the head for movement into the welding area to form a weld about the pipe during rotation of the ring.

Abstract: A Loran-C receiver signal processor is disclosed which processes radio frequency Loran-C signal pulses on a point-by-point, cycle-by-cycle basis to provide the ability to locate on each pulse a tracking point which is used for accurate time difference of arrival measurements between successively received signal pulses or to improve the signal-to-noise ratio of the received signal.

Abstract: A Loran-C navigation receiver is disclosed wherein digital circuitry and a microprocessor is used to automatically identify Loran transmitting stations and makes standard hyberbolic navigation measurements. The receiver operator manually enters a group repetition rate into the apparatus being operated. Initially, the receiver receives and analyzes all received signals until signals from a master and secondary station are received regularly at the stored group repetition rate. The apparatus then changes to a fine search mode in which the exact time of receipt of the master and secondary station signals is determined; the phase code of the received signals is checked to determine if the received signal is a ground or sky wave, and a determination is made if there is a deflective secondary station blink code.

Abstract: A Loran-C receiver cycle detector is disclosed which processes Loran-C signal pulses on a cycle-by-cycle basis of the carrier frequency and generates an output for a specific carrier cycle. Due to received noise, sampling techniques are used to create a histogram which is analyzed to provide feedback used to accurately locate a tracking point on each Loran-C pulse.