This elaborate mixer is from an Electronics Today International from the 80s. Operational amplifiers are common and resistors with no value determine the gain of the amplification steps.
The presented circuit was found in a 90’s Electronic Engineering. The circuit is based on CMOS...
We find the original version of this circuit in an English publication (1986). It is a...
Found in a 1990s Electronics Now, this circuit uses a period-specific integrated circuit that...