This circuit digitally counts input pulses. The circuit from a November 1970 Radio Electronics uses unijunction programmable transistors. Note the counted pulse duration.
This is the simulation of a Ultrasound Receiver using the 741 IC, an operational amplifier....
The resonant circuit depends on the crystal frequency that can go up to a few megahertz. The...
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...