This precision signal rectifier was obtained in an American technical documentation from 1975. The operational amplifiers can be 741 and the power must be supplied from a symmetrical source.
The RF oscillator in the figure provides signals in the range of 7 to 100 MHz, using an overtone...
The maximum frequency of this oscillator depends on the voltage comparator used. For common types,...
Found in a 90s magazine for radio amateurs, this circuit can generate frequencies up to 45 MHz...