This circuit uses an 18 MHz crystal to generate 36 MHz signals. We found it in an 80's documentation. The circuit has an input for frequency modulation.
This VCO makes use of an RC4558 which is an operational amplifier with characteristics close to...
Found in an EDN from the 90s, this circuit uses operational amplifiers from that time, which are...
Found in a Popular Electronics of the 90s this configuration can be seen elsewhere on our site....