I've always had a passion for accurate time. DCF77 clocks in the house, NTP synced computer clocks. GPS/PPS synced NTP daemons..
And recently, with surplus hardware becoming available for very reasonable prices on sales sites like €bay:
- Temex LPFRS-01 - 10MHz from ebay.
- based on G3RUH's design, but using a High Precision Double Oven Controlled Xtal oscillator (DOCXO) (from ebay)
- PCB designed for the this circuit.
Phase comparison over long time interval of the above mentioned oscillators
- using Analog (A/D) to RS232 interface with PIC16F876A
* Due to a bug in the Compiler/Library code I've stopped developing using PIC16F876A. I've now choosen the PIC16F690
- PCB design for this A/D-RS232 interface
- Firmware design, using Microchip MPLAB-IDE, written in Hitech-C
The Ultimate plan is to lock the XO Local Oscillators of my various SHF/Microwave transverters (23, 13, 3cm) to the 10MHz Frequency Standards. An ADF4002 PLL chip from Analog Devices was choosen as it seems the simplest way to lock (Voltage Controlled) Xtal Oscillators up to 400MHz to a (10MHz) Reference Clock.