In the figure we have the way to implement a logic gate or (OR) with an LM393. The circuit must be powered by a symmetrical source and other operational ones can be used.
This TTL circuit for digital signals up to a few dozen megahertz was found in old documentation, but...
This circuit with an operational amplifier was found in the magazine Radio Electronics of...
This detector is from the 1990 Motorola Dataar Databook, but can be adapted to work with more...