The integrated circuit used in this configuration for noise reduction on FM radios is not common today. The circuit is from 80s documentation and the reduction rate obtained is in the 10dB order.
This circuit with pressure sensor was obtained from the Encyclopedia of Electronic Circuits volume 5...
This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent...
This circuit was obtained in Radio Electronics from the 90s. The integrated circuit is uncommon...