In High school and University courses, I have only seen active filters made around OpAmps. I'd like to know something about active filters built with BJT amplifiers.
Figure: Example of BJT filter compared to OpAmp version
I can find lots of information in books I have about OpAmp filters, but nothing about BJT filters. I searched a lot also on the Internet, but I found very little information.
My question is how to design filters with BJTs and what are the advantages/disadvantages versus OpAmp circuits (costs, performances, noise...)?
Moreover, can you please suggest me a good book or some lectures to better understand these kind of filters?