Fellow time-nuts, In the end of the previous millennia I got involved in a handful of email-lists pertaining to analog (musical) synthesizer and building of these. I then ended up with the opportunity of buying some test-gear to aid my endeavors on trimming the oscillators. It's a bit of a challenge, since you have an exponential converter that transforms a 1 V/Oct voltage over to a current linear with frequency, using NP-junction properties. Then this current is used convert into a sawtooth or triangular shape using a capacitor and a reset circuit, of which the later has a fixed reset-time. A good expo-converter can span over 20 octaves. Trimming this to "track properly" and be temperature stable is a challenge. So, I was able to acquire a pair of bench DMMs in form of HP 3457A, a frequency counter in form of HP5335A and a R&S XSRM Rubidium reference out of Ericsson as they closed one of their factories and also calibration labs. Great. I also got a HP4195A network analyzer and HP3325B function generator. Not a bad setup. However, I wanted to learn more about oscillators. I was searching the net using AltaVista, found the NIST T&F archive, I found variour other sources, learned that there is a stability measure called Allan Deviation and phase-noise, and started to read up a lot. I then also found this little quirky email-list for people that really like time and frequency and being kind of nuts, called time-nuts. You might have heard about them. I ended up learning a lot quickly. In parallel at work I was working with jitter in digital transmission and how that cause bit errors, synchronization and how to build synchronization over the full network. I ended up joining the IEEE UFFC, as this allowed me to get access to that library of articles. Over time I have seen my lab outgrow the room it started in, I now lost count of the number of rubidiums I have, I barely know how many cesiums I have and the once unobtainium of a hydrogen maser obviously takes a big part of the new lab and is fortunately easy to count so far (1). Counter-wise I also got a rather sizeable collection, some of which I have more for museum/reference purposes than anything I can meaningful use. I can measure ADEV and phase-noise fairly well, to the level that I was appaulled by the huge 10 ps spikes that the RS232 readout was causing, and here I thought 10 ps resolution was unobtainable not that far ago. I have presented at EFTF and IFCS, have a PTTI presentation to finalize now. I know a whole range of the people behind the names of the articles I read. Over the years I learned a lot just hanging out on the list, and I have hopefully contributed some. It's been an awesome journey. There is still things to learn, and just reading the list is a great way to learn things. Also at times, I find myself reminded rather than learning, but that is important too. Cheers, Magnus On 2021-01-01 06:02, Tom Van Baak wrote: > Hello time nuts, > > Ah, it is 2021-01-01 (JD 2459215.5, MJD 59215) which is nice because > that means it's not 2020 anymore. > > One reason I've been looking forward to 2021 is that it's now > officially the 20th year of the time nuts mailing list. So this is a > note to say *thank you* to everyone for making it so amazing over the > years. I get comments all the time about this mailing list; its depth, > its high SNR, its focus, its vast archive of quality postings, and > especially, the community that evolved around the list. > > On the web the phrase "time nut" is now a proper noun, sometimes an > adjective, or occasionally a diagnosis or disease. Never in my wildest > dreams did I think any of this would happen. I thought my early > interest in nixie tubes, clocks, electronics, and precise timing might > be a passing phase, and that the frequency of eBay purchases would > fade. But no. This turns out to be an incredibly wide, deep, > interesting, and rewarding hobby. The mailing list started with 6 > people (half of whom are still active) and we now have 1850 members. [1] > > Speaking of history, and also to put time-nuts into perspective, I'd > like to mention that leapsecond.com (tvb) and febo.com (jra) predate > Y2K (2000), wikipedia (2001), facebook (2004), youtube (2005), twitter > (2006), reddit (2006), iPhone (2007), duckduckgo (2008), gmail (2004, > 2009), eevblog (2009), instagram (2010), snapchat (2011), outlook > (2012), and literally millions of other web sites and mailing lists. > > When this all started for us it was WWV on short-wave, ACTS by phone, > Loran-C, GOES, WWVB, GPS, Win98, dial-up, and my search engine was > altavista.dec.com. It's scary to think how much has changed in 20 > years. Fun fact: I started leapsecond.com so I could post the results > of a Y2K Colorado visit to NIST. If the world was going to crash I was > going to be at ground zero, with a camera. [2] > > Anyway, stay safe, stay healthy, stay timely. Here's to a new decade > and a happy new year to all of us. > > /tvb > > [1] http://leapsecond.com/time-nuts.htm#history > > [2] http://leapsecond.com/y2k/ > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

-------- Magnus Danielson writes: So what does an analog synthesizer's allan deviation look like ? :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

Poul-Henning, On 2021-01-03 14:39, Poul-Henning Kamp wrote: > -------- > Magnus Danielson writes: > > So what does an analog synthesizer's allan deviation look like ? > > :-) I got distracted :) One of these days. :) Cheers, Magnus

Hi Tom, I admit I'm a little bit late, but anyway congratulation to this huge success. This mailing list and the associated web pages with a huge bunch of information are an incredible treasure. Even though I wasn't able to contribute much to the knowledge concentrated here, it's always a pleasure to follow the discussions that highlight very different aspects of timing. Thanks for all the efforts by you and everyone who's associated, and all the best for 2021 and beyond! Martin

On 1/1/21 4:02 pm, Tom Van Baak wrote: > Hello time nuts, > > Ah, it is 2021-01-01 (JD 2459215.5, MJD 59215) which is nice because > that means it's not 2020 anymore. > > One reason I've been looking forward to 2021 is that it's now officially > the 20th year of the time nuts mailing list. So this is a note to say > *thank you* to everyone for making it so amazing over the years. I get > comments all the time about this mailing list; its depth, its high SNR, > its focus, its vast archive of quality postings, and especially, the > community that evolved around the list. > > On the web the phrase "time nut" is now a proper noun, sometimes an > adjective, or occasionally a diagnosis or disease. Never in my wildest > dreams did I think any of this would happen. I thought my early interest > in nixie tubes, clocks, electronics, and precise timing might be a > passing phase, and that the frequency of eBay purchases would fade. But > no. This turns out to be an incredibly wide, deep, interesting, and > rewarding hobby. The mailing list started with 6 people (half of whom > are still active) and we now have 1850 members. [1] Having just caught up on almost 2 years of backlog, I just want to reinforce what an incredible community this list is. My day job and various other events through 2020 (somehow the pandemic was the least of all) have meant I've done almost no time stuff since mid-2019. The one exception being trying out a comparison of my house rubidium (my old apartment didn't have a usable sky view for GPS) vs the frequency output of a LeoNTP, amazingly, despite the rubidium (an ancient Efratom FRK) being over 20 years out of cal, the two agree past 9 digits on an SRS SR620, one used as reference, the other input, was just the quickest way to get a rough idea.