Difference between revisions of "Frequency Calibration via GPS"
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=== GPS === | === GPS === | ||
| + | |||
| + | * U-Blox NEO-7M GPS Module | ||
| + | ** Programmable frequency from USB | ||
| + | * SMA Female connector | ||
| + | * 5V operation | ||
[[File:NEO-7M-02.PNG]] | [[File:NEO-7M-02.PNG]] | ||
| Line 18: | Line 23: | ||
[[File:NEO-7M-05.PNG]] | [[File:NEO-7M-05.PNG]] | ||
| − | |||
| − | |||
| − | |||
==== U-Center Programming Software ==== | ==== U-Center Programming Software ==== | ||
| + | * TP5 sets PPS output to "any" frequency | ||
* [https://www.u-blox.com/en U-Blox website] | * [https://www.u-blox.com/en U-Blox website] | ||
** [https://www.u-blox.com/en/product/u-center U-Center software] | ** [https://www.u-blox.com/en/product/u-center U-Center software] | ||
* Set to 8 MHz on GPS PPS pin when locked | * Set to 8 MHz on GPS PPS pin when locked | ||
| − | ** Other frequencies have some "jitter" | + | ** Other frequencies have some "jitter" but are still GPS accurate |
* Set to 2 Hz on GPS PPS pin when not locked | * Set to 2 Hz on GPS PPS pin when not locked | ||
Revision as of 11:19, 22 December 2020
Inexpensive Frequency Standard with output synchronized to GPS satellites,
Contents
Features
- Generates very accurate frequency output
- U-Blox NEO-7M GPS Module
- Remote Amplified GPS Antenna
- FTDI-49MM
- 50 Ohm Output
Parts
GPS
- U-Blox NEO-7M GPS Module
- Programmable frequency from USB
- SMA Female connector
- 5V operation
U-Center Programming Software
- TP5 sets PPS output to "any" frequency
- U-Blox website
- Set to 8 MHz on GPS PPS pin when locked
- Other frequencies have some "jitter" but are still GPS accurate
- Set to 2 Hz on GPS PPS pin when not locked
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
