We found this balanced modulator circuit for DSB and possibly SSB transmissions in US 1980s telecommunications documentation. The diodes can be replaced with equivalents.
This simple circuit for a high impedance magnetic phone (500 ohms or more) has been found in a...
This configuration enables the use of low current switches or sensors to control high power loads...
We found this circuit in the 1993 Motorola Linear Interface ICs. The operational is unusual today, but...