Improved methods and systems for amplifying a signal are provided. The bottomhole assembly including at least a motor and a bit is connected to the free end of the coiled casing, and injected into the earth while circulating fluid through the coiled casing to form a drilled earth borehole having a borehole wall. The lead body has an exterior surface. Accordingly, a tensile strength acting in a width direction of the poly-V belt is substantially divided midway between the divided poly-V belts to reduce cracking in the round poly-V belt, resulting in longer life of the poly-V belt. The fixing portion and the blocking portion abut opposite sides of the at least one first sidewall for preventing the at least one first sidewall from leaving a gap between the at least one first wall and the locking portion. In each program loop, the nonvolatile memory device determines a program condition and increments the program voltage by an amount determined according to the program condition.