We found this circuit in the 1982 SGS linear integrated circuit manual. The L149 is not common today and the circuit can be implemented with equivalents.
January 2017 - Mouser Electronics is shipping the new Littlelfuse TVS SP1043, SP1044 and SP1045...
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
This circuit was found in a 90s American publication. The same configuration appears in several...