Hello everyone I have completed my freshman year in EE. For the summer, my professor has asked me to design a lock-in amplifier. First he has asked me to read about AD630. Now after reading the datasheet at (http://www.analog.com/static/imported-files/data_sheets/AD630.pdf), I was a bit confused. I have taken an intro course in circuits and networks(not electronics). The block diagram only used op-amps, resistors and capacitors. Can anyone just explain to me how the thing functions, like how an input signal traverses through the whole structure, undergoing what freq/amplitude/phase changes? Please explain figure 1 on first page and figure 1 on 6th page. Really appreciate your help.