Frequency Calibration via GPS

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Inexpensive Frequency Standard with output synchronized to GPS satellites,

Features

  • Generates very accurate frequency output
  • U-Blox NEO-7M GPS Module
  • Remote Amplified GPS Antenna
  • FTDI-49MM
  • 50 Ohm Output
  • Mini-360 Switching Power Supply
  • 5V out
    • 7-23V in

Parts

GPS

NEO-7M-02.PNG

NEO-7M-04.PNG

NEO-7M-05.PNG

  • U-Blox NEO-7M GPS Module
  • SMA Female connector

U-Center Programming Software

FTDI

50 Ohm Driver (Not Required - nice to have)

  • Used modified PulseGen card to drive 50 Ohms, 5V level output
    • Remove oscillator circuit
    • 5 parallel 74AC14 outputs with 249 ohm resistors on each output
  • Able to drive long 50 ohm coax
  • Square wave output
  • Very fast edges

Videos

  • This is the approach I followed

  • GPSDO vs Rubidium Frequency Standard