I was curious about how fast the ADM3202 RS-232 line drivers were. So, I fed one with 3.3V pulses and looked at the output. Apparently, it takes 100ns before the output moves and then it takes 250ns to go from +6.3V to -6.3V. However, the standard defines anything lower than -3V as a mark, so at that point the serial device should see it. This means only 166ns for the transition or 266ns delay in total. This is significant, but it seems very constant. #electronics #timenuts

Last week I got myself a #TinySA Ultra. It has a signal generator mode, so here I am today comparing its oscillator stability against the bench signal generator using a #NanoVNA reflashed as #TinyPFA.

I was having trouble believing the output of my adev script because it showed such high values, so I loaded up the data in TimeLab which drew the same exact plot. 🤷 I also plotted the measured phase delta between samples. I do *not* think that's thermal (air conditioning) related. #timenuts

I added blanks for readability and a button that cycles through the display modes I didn’t mention I had :)

I still don’t have a real external source of time, so things initialize at 2000-01-01 00:00:00.

Previously, you may have noticed the two AVRs on a breadboard. One is the “oscillator” that generates an IRIG-A signal (this is where the initial date comes from). The second chip parses the IRIG data and issues the necessary SPI commands to display it. #electronics #IRIG #timenuts #clock

It’s alive! #electronics #clock #timenuts

The digits are a glorious shade of red which unfortunately doesn’t show up in the video at all.

This is just the “demo” mode, it is a fully generic SPI-programmed 10-digit 7-segment module. Eventually, it will be used for a clock but until now it just counts.

Woohoo! Looks like my math is right. Both TimeLab and stable32 generated the same exact curve as my script. #timenuts

The problem with trying to write my own script to make a sigma-tau plot is that when I get a weird curve I have no idea if that's because I screwed up my code or because the data I acquired is funky. I suppose I should install stable32 or timelab and see what kind of plot they generate. #timenuts

@dj3ei The design was 1.68V (approx. Vcc/2) for the collector but I measured Vc=1.27V, Vb=1.44V, and Ve=0.80V. My to-Vcc bias resistor is 26.7k instead of the ideal calculated 28.2k, but that can't be the only reason.

It is intended for #CHU time station frequency - 3.33MHz. They use AM, so +-10kHz max.

I wanted to try RF circuit design but even HF is too much for breadboards. However 3.33MHz should work well enough. When I have something I like, I'll rebuild it more permanently. #timenuts

Good news everyone!

IERS Bulletin C Number 65 has just been published, and (as expected) NO #LeapSecond will be introduced at the end of June 2023.

#NTP #Time #TimeNuts

https://datacenter.iers.org/data/latestVersion/16_BULLETIN_C16.txt

Hey #timeNuts does anyone have a citation for Nepal using +05:40 as its UTC/GMT offset during the historical period from approximately 1920 to 1986? The cited source (standard unix timezone database) has +05:30. https://en.wikipedia.org/wiki/UTC%2B05:40

Woah! International Bureau of Weights and Measures has voted to discontinue leap seconds by 2035.
Catch those last few times the clock says 23:59:60 while you can.
#timenuts #leapsecond #timekeeping