Question

Design an audio amplifier that amplifies signals from 20Hz to 20kHz. Your approach should be to use a cascade connection of two first-order passive circuits separated by a noninverting OP AMP. The source has a 50-? series resistor and the output of the filter feeds a 10-k? audio transducer. Design a bandpass circuit with the following specifications all ±5%: fCL =20Hz, fCH =20kHz, B=19,980Hz. Passband gain +40dB. What is the minimum GBW of the OP AMP that can be used in this application? Use Multisim to validate your results.

Answer 1

The unity gain bandwidth of opamp should be much greater than the higher cut-off frequency of bandpass filter.

More the GBW better will be the bandpass filter.

GBW> 10*higher cut-off frequency = 200kHz (which should be good enough)