We found this balanced modulator circuit for DSB and possibly SSB transmissions in US 1980s telecommunications documentation. The diodes can be replaced with equivalents.
The circuit presented emulates an OR gate with the LM3900, operational transconductance amplifier....
I found this simple circuit in an English magazine from 1984. The circuit can be assembled easily...
The basic idea of this circuit is to insert a mark on a signal that is being observed on an...