62 of 78 LAMINI. 4.4 Draw a block diagram of a digital optical receiver showing its various compo- nents. Explain the function of each component. How is the signal used by the decision circuit related to the incident optical power? Solution: Optical signal Photodiode Voltage supply Front end Preamplifier Amplifier Automatic gain control Linear channel Filter Decision circuit Clock recovery Data recovery Data Figure 4.11: Diagram of a digital optical receiver showing various components. Vertical dashed lines group receiver components into three sections.