This Philips circuit of the 70's makes use of components of the time. The DZD40 is an uncommon integrated circuit today.
This circuit came out at a Wireless World in January 2000. The circuit can be easily assembled as it uses...
We found this transmitter circuit for different frequency ranges in a 1992 documentation. The...
This TTL circuit can be used as a shield, controlled by one of the inverters. The circuit must be...