September 2020
The three input buffers isolate the 1 PPS input from the GPS receiver, and distribute it to where it is used: the Time Interval Counter, the rear panel socket (so the 1 PPS can be used for other purposes) and the panel LED. This isn't rocket science, by any means. Don't forget to place a 100 nF capacitor across the chip supply.
The Input Buffers circuit. (Click on the picture for a full-size diagram you can print).
To provide plenty of drive without loading the circuit, each output is driven by two CMOS buffers in parallel. For even more drive, use a separate 100 Ohm resistor from each gate to the output socket. Wire from the board to the sockets with a pair of wires ripped from recycled ribbon cable. This will limit unintended radiation. Don't forget to place a 100 nF capacitor across the chip supply.
The Input Buffers circuit. (Click on the picture for a full-size diagram you can print).Introduction Reference & Dividers TIC Circuit Micro & Misc.
Copyright � M. Greenman 2020. All rights reserved. Contact the author before using any of this material.