Method and associated apparatus of data extraction, including: sampling a signal and obtaining a plurality of sampled values, providing a reference sample quantity when the sampled values transit, providing a unit bit sample quantity according to the reference sample quantity, and corresponding each of the sampled values to each data bit of the signal according to the unit bit sample quantity. Depletion layers are also formed between the N-type regions of the photodiode and a substrate of P-type semiconductor. When the first instance-representation is dropped, the technology identifies, responsive to the step of detecting, one of a plurality of spatial relationships between the first instance-representation and the second instance-representation. The maximum cross-section of the openings amounts to 90 percent. The clock generator includes: an input node coupled to receive the input clock signal; at least one pulse generator coupled to the input node to receive the input clock signal and further coupled to provide a clock control signal; and a control gate coupled to the input node to receive the input signal and further coupled to the at least one pulse generator to receive the clock control signal.