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niconiconi's posts Back to profile
66 posts total
niconiconi

RIP cybre.space, end of an era... cybre.space/~chr/cybre-space-e I'm one of the few Fedi users who have never changed instances, but it's time to move on...

25 Aug 2022 at 18:13 | Open on cybre.space
chjara :hakasenyan: :verified:
@niconiconi damn
such is the nature of this network, without a massive corporate backer it is all ephemeral
25 Aug 2022 at 18:35 | Open on snowdin.town
niconiconi

Q: What do you call a bomb that explodes instantaneously?

A: Atomic bomb.

25 Aug 2022 at 14:43 | Open on cybre.space
NeonPurpleStar :heart_pan:
@niconiconi

Q: Why are the middle ages also called the dark ages?

A: Because there were so many knights.
25 Aug 2022 at 14:47 | Open on outerheaven.club
niconiconi

Q: What does a sysadmin say when a website's IPv6 is unreachable?

A: "AAAA!"

23 Aug 2022 at 15:24 | Open on cybre.space
niconiconi

MFW I realized most quantum experiments in introductory books are just lies to children, they're thought experiments at best. The literal setups as described either never work in practice, or don't really prove their results due to loopholes.

An interferometer with a single photon is the worst offender. Ordinary light sources like lamps or lasers can never work as single-photon sources. Even if you add a huge attenuator and make the light intensity lower than the energy of a single photon, there's still a non-negligible probability that it will emit multiple photons. In fact all experiments before the 1980s had this loophole. Creating true "anti-bunching" single-photon sources requires esoteric techniques. Still, this probability can only approach but not reach 0% in practical devices.

For the same reason, the BB84 quantum key distribution protocol often don't work in practice in its original form. Source or detector imperfections make the original protocol often totally broken. physics.unm.edu/Courses/Deutsc

MFW I realized most quantum experiments in introductory books are just lies to children, they're thought experiments at best. The literal setups as described either never work in practice, or don't really prove their results due to loopholes.

An interferometer with a single photon is the worst offender. Ordinary light sources like lamps or lasers can never work as single-photon sources. Even if you add a huge attenuator and make the light intensity lower than the energy of a single photon, there's...

10.2 FEEBLE LIGHT VS. SINGLE PHOTON 10.2.1 In Search of Feeble Lightâs Wave-Like Properties: A Short Historical Review [...] This pioneering experiment was followed by a long series of diffraction [27] and interference [28-33] experiments with light emitted by strongly attenuated ordinary light sources, mostly discharge lamps, so [...] It was thus concluded that "there was only one photon at a time in the interferometer," and the observation of fringes was then considered a demonstration that "a photon interferes with itself." [...] In the 1970s, the general wisdom was then that “single-photon wave-like behavior” had been experimentally demonstrated. However, revisiting that question in the early 1980s, we realized that, according to the formalism of modern quantum optics as developed by Glauber [12,34,35], none of the experiments cited above could be considered a demonstration of single particle interference, because in none of these experiments the light used could be considered as a single-photon wavepacket. This led us to perform the experiments of [5], presented in Sections 10.3 and 10.4. In the rest of this section, we use the formalism of quantum optics to highlight the difference between single-photon wavepackets and all the types of light used in the experiments above.
The probability of a double detection is thus strictly null in the case of a single-photon wavepacket. This property ("anticorrelation") is not surprising if one remembers that the number of photons is a good quantum number, and its value is 1. Since a photodetection amounts to destroying a photon, there is no photon left to allow for a second detection. In contrast, in a semi-classical wavepacket the number of photons is not a good quantum number, since |Ψ_qc⟩ is not an eigenstate of N-hat , and the probability to have two photons is not null. It is therefore not surprising that one can have two photodetections. This difference allows one to make an experimental distinction between a true single-photon wavepacket, and a quasi-classical wavepacket, even when attenuated enough that the average number of photons is much less than 1. One can then ask: can such a difference be observed, when one takes into account experimental inefficiencies and noise? We will see in Section 10.3 that it is indeed possible to establish a quantitative criterion that renders the distinction presented above fully operational, leading to practical tests in realistic experiments. But before addressing that question, we will ask, still from a theoretical point of view, whether various kinds of strongly attenuated light beams may exhibit an anomalously small rate of double photodetection, by comparison to what is expected for a classical wave.
10.2.8 Conclusion: What is Single-Photon Light? In this section, we have shown that a genuine single-photon wavepacket, i.e., a one-photon state emitted at a well-known time, exhibits a characteristic behavior, the fact that it cannot be detected jointly by two photodetectors (anticorrelation). Such a behavior is not expected in the case of an attenuated beam from a classical lamp, including the case of a discharge lamp where one has single-photon wavepackets shorter than the average time between the wavepackets. The paradoxical behavior in the latter case is resolved when we realize that the problem is the fact that one has no information about the time when any single-photon wavepacket is emitted. We can thus conclude that it is not enough to have single-photon wavepackets to have single-photon light. We need in addition to know at which time each single-photon wavepacket is emitted [40]. This is the case for the two types of sources described below: heralded single-photon sources on the one hand, and on-demand single-photon sources on the other hand.
16 Aug 2022 at 10:41 | Open on cybre.space
niconiconi

Digital electronics be like:
* legendary chip design, begin of a new era
* millions of transistors
* obsolete within 5 years

Analog electronics be like:
* legendary chip design, begin of a new era
* 2 transistors, literally
* still one of the best chips ever invented in the industry 40 years later.

Real physics is hard. #electronics

LTZ1000/LTZ1000A Block diagram A special buried-Zener diode, a heater, and two compensating transistors. That's all.
6 Aug 2022 at 9:49 | Open on cybre.space
DELETED

@niconiconi good old LTZ1000. the go-to device for voltnuts around the world

6 Aug 2022 at 16:35 | Open on cybre.space
niconiconi
niconiconi

A novel concept for a fully digital particle detector, G. Casse et, al. Journal of Instrumentation. iopscience.iop.org/article/10.

Make an SRAM chip that is very vulnerable to Single Event Upsets from radiation, so you can detect particles by looking for bitflips :blobcatgiggle: I think this is not the first time this trick is used. "It's not a bug, it's a feature!" #electronics

2.1 The digital sensor concept Memory cells are digital circuits with two selectable states (0 and 1) used to store a single bit of information. The typical layout of the widely used static random access memory (SRAM) is shown in figure 1a. Four central transistors (Mn1, Mp1, Mn2, Mp2) form two cross-coupled inverters. The operations are performed by setting the write line (WL) that controls the gate of transistors Mn3 and Mn4. The bit lines BTL (nBTL) is driven high (low) by the inverter circuit. For writing, a logic '1' or '0' is applied to the bit lines, the WL is asserted and the set value is stored. Memories are subjected to occasional, undesired state changes induced by crossing ionising particles. These events are called single or multiple event upset (SEU or MEU) depending on the number of digital nodes affected [7]. They cause problems (soft errors) in electronics with high transistor density. Digital circuits are designed to be robust against these, by implementing temporal or spatial redundancy, dummy structures or other mechanisms for correcting their occurrence. Thanks to these measures, SEUs occur at very low rates in modern electronics. Instead, we want a digital device with very high probability of a state change induced by crossing ionising particles. Figure 2. schematics of implemented digital sensor (Dsens) cells: a) circuit level schematic of the improved Dsen1 cell; b) cell layout of the improved Dsen1 cell using UMC 65 nm.
26 Jul 2022 at 4:32 | Open on cybre.space
niconiconi

An Eurorack music synthesizer chassis sounds like the perfect format for anyone who wants an analog computer remake project. Both are designed for knobs and patchcords. #electronics

20 Jul 2022 at 5:16 | Open on cybre.space
niconiconi

Electronics is full of "It's not a bug, it's a feature"-type inventions.

* Inductors stop functioning at high current due to core saturation? Add a control winding to the core, now you can make a magnetic switch or amplifier by driving the core in and out of saturation.

* Diodes burn out and become a short circuit after taking too much power? Put them in a chip as factory one-time programmable fuses.

* Diodes create a large current spike before it turns off due to reverse recovery? Use that spike to make a pulse generator, special Step Recovery Diode can generate picosecond pulses.

* Noise from Zener voltage references is just too strong? Make a standard noise source to test radio receivers.

* Your electrolytic capacitors are really crappy and have high resistance? Use them as free resistive dampers to suppress LC resonance and parasitic oscillations in power supplies. (Yes, replacing crappy capacitors with good low-ESR ones can actually destabilize some power supplies)... #electronics

Electronics is full of "It's not a bug, it's a feature"-type inventions.

* Inductors stop functioning at high current due to core saturation? Add a control winding to the core, now you can make a magnetic switch or amplifier by driving the core in and out of saturation.

* Diodes burn out and become a short circuit after taking too much power? Put them in a chip as factory one-time programmable fuses.

17 Jul 2022 at 16:28 | Open on cybre.space
niconiconi

I still can't forget how people trolled Outlook back then... Outlook used to display the header X-Message-Flag as a GUI banner message, so we had...

X-Message-Flag: WARNING!! Outlook sucks
X-Message-Flag: Warning! Using Outlook is insecure and promotes virus distribution. Please use a different email client.

:blobcatgiggle:

An Outlook mail window, displaying an E-mail from a FreeBSD mailing list, with a banner message showed by Outlook: Warning! Using Outlook is insecure and promotes virus distribution. Please use a different email client.
17 Jul 2022 at 11:04 | Open on cybre.space
Show previous comments
TrechNex

@niconiconi this reminds me of the early versions of iOS when you used to be able to trigger notifications on other people's iPhones by sending a text with *go at the start 😁

17 Jul 2022 at 15:07 | Open on mstdn.social
« ƸӜƷ »
Saxnot

@niconiconi I never really understood outlook messages.

They appear to be E-Mail.
But yet they try to steer away from the technical specification as much as possible.

Outlooks feels like failed en.wikipedia.org/wiki/Embrace,

20 Jul 2022 at 10:35 | Open on chaos.social
niconiconi

I posted a web tutorial about how to build oscillator circuits...

...It keeps receiving positive feedback.

11 Jul 2022 at 15:42 | Open on cybre.space
niconiconi

Q: What do software maintainers say when they're asked to sign an existing version with an added backdoor?

A: We'll just resign.

11 Jul 2022 at 15:32 | Open on cybre.space
niconiconi

Thyristors arrived. Standard TO-220 packages, but they should be okay for a oneshot pulse up to 100+ amps, good enough for my surge generator to blow things up without blowing up itself. ⚡ #electronics

8 Jul 2022 at 7:11 | Open on cybre.space
niconiconi

still waiting for the new isolated DC/DC converters to arrive (I already have some but cannot find them anymore) before I can start the pulsed power experiments... It's not technically required but I assume allowing 200 volts to flow back into your logic circuits really isn't a good idea... #electronics

11 Jul 2022 at 9:51 | Open on cybre.space
niconiconi

- start Project.
- start Subtasks 1, 2, 3 ,4
- finish Subtask 1, 2.
- the best way to do Subtask 3 is a somewhat open-ended problem
- research Subtask 3 before losing interests due to dificulties, no practical results ever came out of it.
- never complete Project.

4 Jul 2022 at 14:58 | Open on cybre.space
chjara
@niconiconi i am in this post and i don't like it
4 Jul 2022 at 14:59 | Open on disqordia.space
Tᴀᴋᴀɴᴀsʜɪ Hᴏʀᴏ

@niconiconi I'm in the second-to-last step right now

4 Jul 2022 at 15:10 | Open on sn.angry.im
Zudlig Ravel Annon
@niconiconi I'm with you except I more often start by working on sub-task 5 or 6.
4 Jul 2022 at 15:32 | Open on expired.mentality.rip
niconiconi

War is Peace, Freedom is Slavery. RAID is Backup. SMS is 2FA. Ketchup is Vegetable.

1 Jul 2022 at 17:48 | Open on cybre.space
Rysiekúr Memesson 🇺🇦

@niconiconi you forgot "Moving to the Cloud™ is a reliability-maximization strategy".

1 Jul 2022 at 17:49 | Open on mastodon.technology
niconiconi

"Wait, you guys are getting paid?!" #animeirl

r/AskReddit: You've paid $500,000 for each month you can live in solitude. You have unlimited food, drinks and entertainment of your choice, but 0 interaction with another living being. How many months do you sign up for? anime girl: You guys are getting payed?!
28 Jun 2022 at 4:27 | Open on cybre.space
Show previous comments
Haelwenn /элвэн/ :triskell:
@niconiconi
> 0 interactions with a living being

Uuuh, entertainment without any interactions?
28 Jun 2022 at 6:48 | Open on queer.hacktivis.me
祢洛子

@niconiconi BTW, do you know who referenced Futaba Sakura in the bottom of the picture ?

28 Jun 2022 at 7:08 | Open on moe.cat
Anonymous
niconiconi

#TIL Unlike ISO and IEC standards, most ITU standards are free to the public! All ITU-T Recommendations are published at itu.int/rec/T-REC/en You can find all the familiar names: V.92, X.25, X.509, or H.264 (800 pages) There are even epub files for some new documents. #electronics

International Telecommunication Union ITU-T H.265 (08/2021) TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services – Coding of moving video --- High efficiency video coding
INTERNATIONAL TELECOMMUNICATION UNION ITU-T V.92 (11/2000) TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES V: DATA COMMUNICATION OVER THE TELEPHONE NETWORK Simultaneous transmission of data and other signals ----- Enhancements to Recommendation V.90
25 Jun 2022 at 11:41 | Open on cybre.space
Jorin, Subcontra Sorceress
Andreas, DJ3EI, he/him

@niconiconi
They even still have a recommendation on Morse code (#CW). ITU started as "International Telegraphic Union" long time ago... Some recommendations given in that document do not coincide with the actual practice of the #hamradio CW sub-community, the most sizeable community that still does it.

25 Jun 2022 at 13:02 | Open on mastodon.radio
PulkoMandy

@niconiconi other places where you can find free standards:
- ECMA for lots of computer stuff, including the ISO9660 filesystem, physical specs for floppy discs, ANSI escape sequences, JSON (ECMA-404), the C# language, the windows 3.11 API, … (several are republications of ANSI or ISO standards, but for free)
- DVB for all things TV broadcast and satellite communications (famous for the way they encapsulated IP packets in MPEG frames to repurpose their TV stuff into internet stuff)

25 Jun 2022 at 15:30 | Open on mastodon.tetaneutral.net
niconiconi
niconiconi

Q: What do you say when a chip designer is eating snacks at work while testing new silicon?

A: On-wafer measurement.

6 Jun 2022 at 0:09 | Open on cybre.space
niconiconi

Literally me, except I'm not a cute anime girl. #animeirl

anime girl at computer: "I have no idea WTF I'm doing LOL"
5 Jun 2022 at 14:47 | Open on cybre.space
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