In the figure we have 3 oscillators with logic gates that can be triggered by external logic signals. The circuits were found in the Radio Electronics magazine of April 1987.
Another of the many tachometer circuits we have on our site. This one is from the September 1976...
This filter for receiving audio in telegraphy was found in a magazine 73 for radio amateurs, in an...
This filter was found in an 80's English publication. However, it can be implemented with modern...