We found this circuit in a 1980s Motorola documentation. The circuit makes use of common operating and the voltage depends on the used type. The components are for a frequency of 500 Hz.
In the figure we have a Texas Instruments circuit for TTL interfacing using discrete transistors. The two...
This circuit was found in Radio Electronics magazine from June 1963. The range is small and the...
The project presented in a 2009 documentation is intended for radio amateurs operating in the...