This circuit was found in an American documentation from the 1980s. The circuit combines filters of different types in a single structure, each of which can be programmed for a frequency.
This transmitter with FET in counterphase was obtained in a documentation from the 90's. The...
Other operational amplifiers of the same series can be used on this circuit found in Motorola's Linear...
Found in documentation from the 1980s, this circuit can generate signals in a range that reaches a few...