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TCXO

A collection of 18 posts

ntp

NTP server frequency stability

Stratum 2+ NTP servers have multiple potential sources of error, let's experiment with lowering them.

  • Dan Drown
6 min read
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

History I'm bringing my RTC Hats [https://blog.dan.drown.org/tag/stratum2/] back online (source code [https://github.com/ddrown/stm32-input-capture-f031] and hardware design [https://github.com/ddrown/stm32-input-capture-f031/tree/master/hardware]

  • 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 [https://blog.dan.drown.org/tag/stratum2/] was to have a more stable local frequency. This is useful when you can't reach your upstream

  • Dan Drown
2 min read
TCXO

TCXO aging part 2

The previous data I have on aging [https://blog.dan.drown.org/tcxo-rtc-hats-aging-rtc-frequency/] covered 10 days, and now I want to come back to this now that more time has passed. This data

  • 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 [https://blog.dan.drown.org/tcxo-rtc-hats-initial-data/], picture [https://blog.dan.drown.org/tcxo-rtc-hats/], other stratum 2 posts [https:

  • Dan Drown
3 min read
ntp

TCXO RTC Hats: Initial data

The TCXO RTC hats [https://blog.dan.drown.org/tcxo-rtc-hats/] are collecting data. I'm focusing on the RTC part in this post. See also: other stratum 2 posts [https://blog.dan.drown.org/

  • 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 [https://blog.dan.drown.org/temperature-compensation/], I measured the TCXO to fit a frequency vs temperature curve. Frequency vs Temperature curve Below are the final curves that I went

  • 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 [https://blog.dan.drown.org/frequency-synchronization-without-phase-in-ntp/]. The sensors are: one built

  • Dan Drown
3 min read
time

Frequency synchronization without phase in NTP

I've been working on my high accuracy RTC project [https://blog.dan.drown.org/stm32f030-devboard-with-tcxo/]. Here's a picture of one of the two systems: Connections The TCXO devboard, BME280, and PCF RTC are

  • 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 [https://blog.dan.drown.org/tcxo-beaglebone-black/], I wanted to get a 24MHz TCXO working. Trial #1 I bought a set of three undocumented 24MHz TCXO's off ebay

  • Dan Drown
4 min read
navspark

TCXO + Beaglebone Black

I've added support for an external clock (TCLKIN) to the Beaglebone Black timer driver [https://blog.dan.drown.org/beaglebone-black-timer-capture-driver/]. Setup I used what I had on hand to test it. I setup

  • Dan Drown
2 min read
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