In a TDMA optical network, a clock data recovery module uses signal oversampling and preamble correlation together with enhanced performance modules to extract additional data from the upstream transmission signal. Thus, the rack of the drive unit meshes with the gear of the rotation unit, so that the rotation disk is rotated rapidly to reach the destined tension unit, thereby facilitating a user adjusting the values of the pulling stress so as to control the pond and tension required for stretching the strings of a tennis or badminton racket. The circuit includes a first series interconnection of a first LED group, a first transistor, and a first resistor, and a second series interconnection of a second LED group, a second transistor, and a second resistor. When the movement direction is opposite to the intended movement direction, the braking force is increased to control the movement in the opposite direction, such that the movement changes from the opposite direction to the same direction, and finally, smooth starting in the desired direction is executed. The initiation of the second fracture is characterized by a second orientation line. The side of the zone of the second conductivity type facing the drain zone forms a first surface, and in the region between the first surface and a second surface located between the first surface and the drain zone, comprises areas of the first and second conductivity type nested in one another.