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TCXO

A collection of 17 posts

TCXO

TCXO RTC Raspberry Pi Hat, part 2

The motivation for this project is NTP servers in datacenters - it can be expensive to get a GPS antenna on top of other people's buildings with a wire running down into your

  • Dan Drown
4 min read
ntp

TCXO RTC Raspberry Pi Hat

HistoryI'm bringing my RTC Hats back online (source code and hardware design is on github). I originally designed it for frequency synchronization without phase alignment. I was going to write my own program

  • Dan Drown
3 min read
gps

GPS module measurements, part 3

GPS module comparison: NEO-7N vs NEO-M8N

  • Dan Drown
3 min read
gps

GPS module measurements

Starting point I got a u-blox NEO-6M and I wanted to compare it to my NS-T. Since I don't have a frequency counter, I decided to try creating one myself. The hardware I

  • Dan Drown
4 min read
stratum2

Drift

One of my goals with the RTC Pi Hats was to have a more stable local frequency. This is useful when you can't reach your upstream clock. GPS modules lose signal from time

  • Dan Drown
2 min read
TCXO

TCXO aging part 2

The previous data I have on aging covered 10 days, and now I want to come back to this now that more time has passed. This data is from the same Pi Hat

  • Dan Drown
1 min read
ntp

TCXO RTC Hats: aging & RTC frequency

I'm focusing on oscillator aging and RTC frequency in this post. See also: initial data, picture, other stratum 2 posts I've been letting these boards run to see what happens. My TCXO's aging

  • Dan Drown
3 min read
ntp

TCXO RTC Hats: Initial data

The TCXO RTC hats are collecting data. I'm focusing on the RTC part in this post. See also: other stratum 2 posts Required picture This hat is on an Odroid C2. The GPS

  • Dan Drown
3 min read
ntp

TCXO RTC Hats

My new stratum 2 NTP server hats arrived from Macrofab today! I have a few hand soldering things to do (32khz crystal and headers), and then I can start calibrating them.

  • Dan Drown
1 min read
time

Temperature compensation, part 2

In the last part, I measured the TCXO to fit a frequency vs temperature curve. Frequency vs Temperature curve Below are the final curves that I went with for the two systems, and

  • Dan Drown
4 min read
time

Temperature compensation

Temperature effects are usually the largest source of frequency changes in clocks. So I have three temperature sensors on my test system. The sensors are: one built into the stm32 chip, a TMP36

  • Dan Drown
3 min read
time

Frequency synchronization without phase in NTP

I've been working on my high accuracy RTC project. Here's a picture of one of the two systems: Connections The TCXO devboard, BME280, and PCF RTC are all on the i2c bus. The

  • Dan Drown
4 min read
rtc

RTC comparison

Real Time Clocks I bought two high accuracy RTC (real time clock) modules and wanted to compare them. RTCs are useful for very low power clocks. They can run for years off of

  • Dan Drown
3 min read
stm32

stm32f030 devboard with TCXO

I'm interested in making a high accuracy real time clock (RTC). To experiment with the hardware I need for that, I created a development board based on the STM32F030F4P6 (which is a 20-TSSOP

  • Dan Drown
4 min read
ntp

GPS PPS drift when it has no signal

Question: What happens to a GPS receiver's pulse per second (PPS) when it loses signal for a long time? To answer this, I first moved the antenna away from the window and put

  • Dan Drown
3 min read
gps

TCXO + Beaglebone Black, part 2

Starting from the previous TCXO modification, I wanted to get a 24MHz TCXO working. Trial #1 I bought a set of three undocumented 24MHz TCXO's off ebay for $6. I was hoping that

  • Dan Drown
4 min read
navspark

TCXO + Beaglebone Black

I've added support for an external clock (TCLKIN) to the Beaglebone Black timer driver. Setup I used what I had on hand to test it. I setup a Navspark microcontroller to send a

  • Dan Drown
2 min read
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