I read on a source from a paper from John D. Ramboz that explains: The incremental pitch-advancement of the coil's helical winding sums over its circumferential length to create an undesirable one-turn loop normal to the axis of the coil (the plane of this loop is parallel to the surface of the paper). Any magnetic flux normal to this loop (in or out the paper surface) induces an error voltage into the coil's output.... ....To compensate for this undesirable one-turn loop, another one-turn loop is place inside of the helical winding in the opposite direction to that of the pitch advancement. It is connected electrically in series with the coil output. In theory, a compensation voltage is induced equal and opposite to that induced in the pitch-advancement loop. This, under certain flux condition, cancels the errors caused by the one turn pitch loop when both are exposed to the unwanted flux. (The arrows indicate the direction of winding) What I don't understand are: 1. What does pitch-advancement mean? I know that 'pitch' in this case means the distance between the windings. But I don't understand the sentence: The incremental pitch-advancement of the coil's helical winding sums over its circumferential length... 2. How does this pitch-advancement create extra one-turn loop normal to the axis of the coil. I cannot visualize it at all. I hope somebody can help me to understand this. Thank you.