Built an active audio filtering system completely from scratch. The filters are powered by an ACDC converter which outputs +/- 15 V. The bass bandpass filter consisted of two cascaded, second-order, inverting active filters. The resulting cut-off frequencies were 140 Hz and 360 Hz with a roll-off rate of -40 dB/dec. The treble bandpass filter consisted of an inverting op-amp followed by two cascaded infinite gain multiple feedback active filters. The resulting cut-off frequencies were 7.9 kHz and 10.4 kHz with a roll-off rate of -40 dB/dec. Also built an A2D converter which lights up a bar LED according to the amplitude of the bass channel.
Read the full report here.