We find this circuit in a 1980s Linear Technology documentation. The circuit can be implemented on the basis of more modern equivalent components.
This dual time constant circuit was found in the October 1987 issue of Radio Electronics magazine. The...
Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine....
This circuit uses only one NC75Z04 port from ON Semiconductor, but it can be implemented with...