A receiver including an apparatus for generating complex four-phase pseudo-random code sequences which may be directly mapped to a quadrature phase shift keying signal constellation. Each of the clamps is configured to receive one of the pair of sliding prostheses and has clamping jaws configured to interact with the side edges of the corresponding sliding prostheses. The optical sensor may include a semiconductor substrate in which various circuit components, one or more photodectors andor a light source may be fabricated.