This filter was found in an 80's English publication. However, it can be implemented with modern operating systems. The circuit can tune frequencies in a range from 10,000 to 1.
This circuit is from the 1974 Motorola Unijunction Trigger Circuits for Gated Thyristor. The triac...
Found in old American documentation, this circuit can divide the frequency of a signal by 2 or 3...
This transceiver is also low power, but this time, it can generate signals in the 144 MHz band. In the...