A frequency divider includes a transmission gate, a first inverter, a first switch circuit, a second switch circuit, and a second inverter. A first contact member can extend from the base laterally adjacent to the first crimping structure. Such complexes include the ruthenium bisphosphine complex 22Ru\u2550CHPh and the ruthenium carbene complex 2Ru\u2550CHPh. The optical pickup further includes an aberration correction lens assembly located between the light source and the object lens. The invention also discloses high pressure liquid chromatography methods for analysis of daptomycin purity. The frequency divider divides the oscillation signal to produce the feedback signal.