We found this circuit in Ferranti's 1974 transistor manual. The components are from the period. The table gives the value of C1 for different frequency ranges.
This circuit is from a specialized documentation in 1992 FETs. The L1 coil has 0.07 uH with...
The LM1468L can also be used. The circuit is from Motorola's Linear Interface ICs and the...
This low frequency doubler requires a 50 mV signal at the input. The circuit is from an old...