The present invention provides an improved clock synchronization algorithm for a distributed system intended for real time applications by performing at the same time an off-set correction and a clock read correction at each node of the distributed system. An autonomous in-vivo device may include a magnet to detain at least a portion of a sample collected from a body lumen; a sensor to sense a property of the detained sample portion; and a transmitter to transmit data of the sensed property. The fuel feed conduit has a pickup inlet which opens into the fuel tank body, allowing fuel to be drawn outwardly by a fuel pump of the fuel injection system. The master frame can be provided with liner support structures along the jambs to receive jamb liners in snap-fit. The difference in amplitude of the dipulses represents the head position signal. The first planetary gear assembly has an axis of rotation that substantially aligns with the axis of rotation of the driving shaft.