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
ntp APU2 NTP server I bought an apu2c0. I believe it will make a better NTP server than my other NTP servers.
gps GPS module measurements, part 2 After the previous tests [https://blog.dan.drown.org/gps-module-measurements/], I ordered another GPS antenna to improve the signal conditions. They're just the cheap puck style antennas with SMA connectors ($10 on Amazon)
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
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
ntp PPS over USB Goal For keeping your system clock on time, you can't beat the Pulse Per Second (PPS) signals available from $10 GPS modules. They typically have better than 100 nanosecond accuracy [https://blog.dan.
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
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
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
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
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
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
time Decoding WWVB, part 2 I worked on detecting the timing information from the WWVB signal. Being able to locate the start of the second is important because it is the clock the data is encoded against. I
time Decoding WWVB I've been playing with decoding WWVB. I have a random wire [https://en.wikipedia.org/wiki/Random_wire_antenna] antenna connected to my sound card's line in jack. The sound card is a
navspark Navspark NTP stratum 0 clock Project Goal I want to create a stratum 0 NTP clock that does not require soldering or any special hardware. It should only require a USB port and software. It should have at
arduino Navspark UART/USB bridge I created a program on the Navspark to send characters at 150 microsecond intervals and then received them on a PC. Below is a histogram of how long it took between characters: The
navspark Navspark timer drift, #2 Second run, this time comparing the Navspark's internal CPU clock against the GPS time. Samples of both clocks are taken once per second, and the amount of time that has passed is calculated
navspark Navspark timer drift The Navspark is a microcontroller with a GPS peripheral. It runs the GPS navigation/timing code as a binary-only library, and uses the Arduino IDE/environment. I have custom code printing timestamp markers