Abstract: A downhole measurement assembly comprising a metal casing housing a plurality of tool sections, one of which includes a detector sensitive to a magnetic field, and a DC power supply for said tool sections, the power supply and the tool sections being electrically connected to the casing, characterised in that the power supply is connected to at least one tool section via a switching circuit and a conductor arrangement, the switching circuit comprising a capacitor, a plurality of switches and control means operative alternately to charge the capacitor from the DC supply and discharge the capacitor through said at least one tool section using the conductor arrangement so as to inhibit the generation of an electromagnetic field in the conductor arrangement between the capacitor and the said at least one tool.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may include receiving a received signal, such as a substantially sinusoidal signal, provided by a driven element, such as a magnetostrictive device, coupled to a non-atmospheric medium and an amplifier having substantially zero quiescent current in the absence of an input signal, wherein the amplifier is to receive a pulse modulated wave comprising an original signal substantially similar to the received signal.