This is the circuit of a commercial radio sold in Japan in the 1960s. The IF is 455 kHz, and the supply is made with a voltage of 9 V. The radio receives stations in the medium wave range.
The interesting circuit shown in the figure, can have its gain digitally controlled and present two...
This circuit that has a response from 10 Hz to 700 kHz was found in Philips documentation from 1968. Dual...
This circuit is from a 1976 Motorola CMOS manual. It can be implemented with modern Darlingtons like...