[HN Gopher] Soyuz spacecraft digital clock teardown
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Soyuz spacecraft digital clock teardown
Author : nucatus
Score : 92 points
Date : 2021-01-19 14:12 UTC (8 hours ago)
(HTM) web link (www.righto.com)
(TXT) w3m dump (www.righto.com)
| CaliforniaKarl wrote:
| You can also watch the companion YouTube video series, at
| https://www.youtube.com/playlist?list=PL-_93BVApb5-951yH6TlP...
| LeonenTheDK wrote:
| Frankly I can't recommend the rest of his channel enough. I
| found the teletype restoration series[0] particularly
| interesting. It's fascinating watching the process of
| troubleshooting and performing repairs of all this vintage
| technology.
|
| [0]
| https://www.youtube.com/playlist?list=PL-_93BVApb5-9eQLTCk9x...
| baybal2 wrote:
| > You might expect the power supply to be a simple buck
| converter. However, the power supply uses a more complicated
| design to provide electrical isolation between the spacecraft and
| the clock. I'm not sure, though, why isolation was necessary.
|
| A reason very simple, you don't want a short through the clock to
| set your space, or aircraft on fire!
|
| A big reason why a lot of avionics still works on HF AC power,
| and not DC is that it makes isolation, and providing arbitrary
| voltages very easy.
| berns wrote:
| Previous discussion:
|
| https://news.ycombinator.com/item?id=22077019
| timonoko wrote:
| Major Error Detected. Soviet resistors are not ubiquitous "Green
| Cylinders". Greens are %5 and reds are 10%.
| jessriedel wrote:
| > Why is the clock so complicated? In this blog post, I examine
| the clock's circuitry and explain why so many chips were needed.
|
| Thousands of words follow before getting to the answer. What is
| the point of such a tease in a technical blog post with no
| advertising?
|
| Do people think this makes good writing? Have authors
| internalized the clickbait style they read in so much other
| media? It's too common to be accidental.
| nucatus wrote:
| If you follow the youtube video posted at the end of the
| article, you will see that there are another two separate
| youtube videos as followup of the first one where some of
| technical details are discussed.
| yellowapple wrote:
| Do you not consider the explanation of the various functions of
| the clock - and the examination of the components implementing
| those functions - to be part of that answer? Because I do;
| pretty hard to answer "why?" if you can't even answer "what?"
| and "how?".
| jessriedel wrote:
| The author successfully summarizes the answer in the section
| labeled "conclusions", so no, this is not the explanation.
| That summaries do not contain all the info of what's
| summarized does not mean they are useless or impossible.
| DWakefield wrote:
| Or maybe he's stating the thesis for his post and then backing
| it with technical detail before writing his conclusion. Have
| readers become so accustomed to instant gratification that they
| can't take the time for a thorough analysis with facts and
| technical detail to back up the author's claim?
| billfruit wrote:
| Nothing wrong with providing a summary and later expanding it
| in a full treatment. There is no need served by holding
| reader in surprise till the ending like a piece of fiction.
|
| I see "story telling" as an anti pattern in non fiction,
| jounralistic and technical writing.
| jessriedel wrote:
| Academic writing uses abstracts, and it is not because they
| are so accustomed to instant gratification. It is because it
| makes for clearer reading and a more efficient allocation of
| effort.
| squaresmile wrote:
| This is not academic writing though. This is an interesting
| story posted on somebody's blog. If I tell my friends a
| cool story, I would need to walk them through the story and
| drop the punch line/conclusion at the end. I also enjoy it
| very much when somebody tell me a story that way. Not
| everything, even technical teardown, needs more efficient
| allocation of effort.
|
| Interestingly, this is the second time I see this kind of
| comment recently and turns out it's from the same person.
| Maybe I'm on HN too much.
| jessriedel wrote:
| I brought up the academic example specifically to rebut
| DWakefield's argument that the main reason the reader
| would want abstracts/summaries is because they cannot
| delay gratification; I wasn't arguing that blogs should
| have it _because_ academics use it.
|
| Clearly, this is my axe to grind
| aeturnum wrote:
| As is standard most serious writing formats, the answer to the
| question(s) posed at the start can be found in the conclusion.
| You are free to read the conclusion any time you want. For
| example, I've heard that the best way to read academic papers
| to read these sections in this order: abstract, intro,
| conclusion, methods. You can read other sections if you would
| like, but the core of the papers' message will be in those 4.
| The rest of the paper provides details.
|
| I do think that more structure would make the blog post easier
| to read and navigate, but since the information you were
| seeking is easily found within the structure that exists, I
| don't think your critique makes much sense.
| jessriedel wrote:
| The standard for most serious writing formats is an
| _abstract_ where the important results of the paper are
| summarized, and an _introduction_ where the author lays out
| the structure of the document. And in something shorter
| without as many sections, you still say the important bits up
| front.
|
| As the second paragraph of my comment makes clear, the point
| isn't to critique this particular blog post, it's to wonder
| why, when the author raises the question, he doesn't then
| just immediately summarize the answer in one sentence, and
| why this is so generally common across so much writing. I
| really do think this is a general phenomenon rather than an
| isolated issue.
|
| (Also, just as a datapoint: On this separate HN thread I
| pulled out the conclusion of the OP and posted it as a
| comment. Even though it was very easy to find since it was
| simply the last two sentences of the post, readers apparently
| found my comment extremely helpful and it was upvoted more
| than 100 times. https://news.ycombinator.com/item?id=25742276
| )
| jbay808 wrote:
| Unfortunately, the common pattern for an academic abstract
| is something like:
|
| _In this paper, the Soyuz clock is analyzed in detail and
| the underlying reason for its high complexity is
| described._
|
| You still usually have to access the full paper to get the
| reason itself...
| jessriedel wrote:
| I agree that this happens all the time in academic
| writing and it's terrible.
| macksd wrote:
| If you only want an answer to that question, I guess so, but
| answering that question is far from the only purpose of the
| post, as stated. I found it far from clickbaity. The title of
| both the article and the HN post imply it's more a story about
| how they tore it down and all sorts of internal details.
| jessriedel wrote:
| It's not that I just want the answer, I want to know the
| answer so I can judge whether the lengthy exposition is
| likely to be interesting and so worth reading.
| aulin wrote:
| the beauty of written content, you can skim the whole text in a
| few seconds, see if it interests you, jump to the conclusion,
| go back and read it all... in a world that's turning completely
| to video content, I'd say we can forgo the supposedly not so
| good style.
|
| OTOH, he doesn't seem to really answer the real question: why
| they still used TTL when much more highly integrated CMOS
| technology was already available in consumer market? I guess
| it's something very specific to aerospace strict standards, and
| as far as I can tell he didn't say much about it.
| rlaanemets wrote:
| Aren't older TTL more resistant to radiation because of
| physically large chip structures? It could be that those
| chips were already space-tested or radiation-hardened.
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