A function of improving accuracy of the extraction of pitch information in an audio signal including voice and sound signals is implemented. The operation of the foot-rotating disc imparts a motion to a lateral post coupled with the handrail frame such that the hands and the feet rotate in opposite direction. The permuted inputs are factored in two or more parallel PFA circuits that comprise adders and multipliers arranged to accommodate any size F-point DFT. The net unit is provided with an alarm to indicate if a diver tries to penetrate the net. The single-arm bail of the unlocking and resetting device can return the start position automatically without manual repositions.