This circuit was found in a 1980s documentation for amateur radio. The circuit is for 9 MHz signals and values in parentheses for FI of 455 kHz. The circuit can be adapted to other frequencies.
The 4028 CMOS IC not only contains the complete decade counter, but also the 7-segment decoder...
Found in an EDN from the 90s, this circuit makes use of integrated circuits of the time, some of...
With this circuit a logic output signal from a microcontroller or other digital TTL configuration can...