Radio och Television (Feb 1962, Nr 2)

A friendly soul has left a magazine in my university mail box. Yet to find out who. But it is a 56 year old magazine called “Radio och Television”, issue number 2 from February 1962.

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Pleasant reading! Remember that this is the beginning of the transistor revolution (arguably it started some years earlier, maybe in 1957 when the traitorous eight left Shockley in his lab and started with Fairchild Semiconductor. Nevertheless, in the magazine we find an interesting article on a home-made transistor amplifier for high-fidelity music. Stereo, even.

There are a lot of different ads offering you to buy the latest available silicon-based diode and transistor.

There is also an interesting article on “Project echo“. This is back in 1962. Sputnik was launched some years before that and some dozen of satellites were back then circulating the earth. But none of them were used for telecommunications.

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Now, you could of course read the wikipedia page, but that was written after the project was done (it lasted from 1960 to 1964). The above article was written at the middle of the project. The Americans launched aluminum-coated balloons that would act as reflectors high up in the sky (1600 km !), like a satellite. Using the reflector they could hurl 960.05-MHz radiowaves in one direction and 2.39 GHz in the other. The transmit power was up to 10 kW for the FM modulated signals. The balloon was located using an overlayered radar beacon and a precalculated assumed trajectory (stored on punch tape). The punch tapes gave the radar a first position where to search for the balloon and then it was fine tuned using the radar beacons.

Then, later that year, the R2-D2-inspiring Telstar satellite was launched and even though it only orbited for half a year and only produced a 2-W output signal, it could still convince humanity of the possibilities and importance of telecommunications.

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… Text … Esc-mm … Esc-mp … Text …

Over lunch the other day, I promised to write a post on this rather quiet forum… so what to write about? Weather? Politics? Illnesses? Trump? Maybe something more important: word processing software.

The other month I had to go back to some old files we created some 20 years ago (like a Ph.D. dissertation, a text book, and a course text book, and other things). It was time to revisit a dear old friend of mine: FrameMaker.  We used FrameMaker a lot at the University back then and then later also at Ericsson and Infineon.

FrameMaker is nowadays owned and developed by Adobe (well since 1995, but it feels like yesterday :o). It was initally created by the Frame Technology Corporation, but is now revamped, quite a lot.

And with this revisit, I have mixed feelings…

  • First, I used to work – a lot – with FrameMaker on unix back in the old days with a slightly different look-and-feel. The Windows version was – and still is – not really the same experience. The pods, for example, cannot be resized. For example, the equation pod could in the unix environment be maximized which allows you to see all panels at the same time. Perfect for fast maths typing. See below.

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  • Secondly, it tends to crash quite frequently on Windows 10. If that relates to the software or the operating system…

Getting back to the maths typing: quite soon, though, one adapts the keyboard short-cuts: esc-mm for a new medium equation, esc-mp to shrink that equation to minimum size, esc-me to expand it to modify the equation, etc. Annoyingly, however, they have removed the shortcut for, arguably, the most important notation: subindex. Rather than typing the equation in one-flow, you have to interrupt and bring the mouse pointer over to the pod and press on the subindex operator. And with Windows’ strange mouse-over-window focusing it quickly becomes a bit frustrating.  (Well, there are other things in the world to worry about… but yet for its intended purpose…)

 

There are perks, however, with the equation editor: it can do calculations for you, simplify your equations, sort, and reshape, etc. It requires a bit of training and thinking, but once you have it up and running, you can quickly type an equation and then do the manipulations and go towards a resulting, compressed equation demonstrating your results.

A benefit is that FrameMaker also schooled us in using paragraph and character designers and styles. Like latex it made it very easy to change the whole layout of your document if you had to change from one format to another. A few clicks and done. Based on the horrific (well…) Word documents I see and get sent to me, I realize that the art of typesetting a document is sort of lost. “… Did you just press the ‘B’ button to make the text bold? …”

In short, I think FrameMaker is a really good alternative to LaTeX of any kind. It is a good wysiwyg and allows you to compile large, complex documents, and I will give it some more days here now and see where it can bring me. But it is expensive …

There are discounted subscriptions to use the tool on a monthly basis and if you have the opportunity ask your employer to give you access and give it a try. There are interchange formats to bring back and forth from and to other commercially available tools.

The title of this post? Short-cuts. For me FrameMaker is shortcuts. Tragically, the keystrokes and four-key short-cuts are still in the fingertips. After 20 years…

Ok, back to writing … esc-vB … ctrl+9 Eq … esc-me … esc fs

Anyone else using FrameMaker out there?

Revisiting the transmission speed

A while ago (several years, in fact) I published a post on the speed of modems, i.e., digital communication. And since I am currently involved in two fiber-to-the-home projects I felt it was time to revisit the chart. I also notice that I could not find too many graphs that have been updated the last few years.

So, the story was to understand what kinds of speed that are offered to the user (and the backbone to distinguish them). In the previous post it was briefly pointed out why the speed increased, i.e., evolution accelerated, the last twenty years. If one plots the transmission speed for a subscriber line, it does not fit to an exponential trend line, nor any good polynomial interpolations either.

Let’s get (to) the picture first. [Click on the image to get to the google spreadsheet’s chart – there might be some more points added as time passes by. WordPress does not allow embedding google charts]. All transmission speeds are in bits per second. For the sake of clarity (?) I also added the population growth (blue line) where the numbers are in Millions. (Since it is a logarithmic scale it is just a matter of moving the blue curve up and down – it looks rather flat anyway).

speed

 

Legend

  • Red stars: telephone lines, teleprinters, wireline modems (POTS, ADSL, ISDN), as well as optofibres (the right-most, top-most red stars).  One could argue about the use of optofibres here, but I go by the connected-via-a-cable concept.
  • Green pyramids: Radio (and optical systems). We see the development of radio standards for subscribers: 1G through 5G, Wifi. Notice the two green dots on the left-hand side! These are the early telegraphs. One of them being the Chappe telegraph system and the other being the Swedish system developed by Edelcrantz. Fascinating stories themselves.
  • Pink bullets: Backbone speeds. Here I have bundled radio, optical, fibres, telephone lines. I have also added some of the more experimental recent results – some claiming to have reached speeds at 1.5 Pbps, i.e., 1.500.000.000.000.000 bits per second. That’s ridiculously fast – about 30000 movies … per second.
  • One could argue that some telegraph systems should be treated as backbone (pink) rather than subscriber (red). However, as long as there was no concept of frequency-division multiplexing or similar coding formats, only time-domain multiplexing, i.e., only one message sent at the time over the line, I count them as subscriber lines instead.

Caveats

There is somewhat of a mess in terms of how speed is reported for all these various formats. The sources refer to measures such as: bits per second, words per minute, symbols per minute, symbols per second, baud rate, etc. For example, the Edelcrantz machinery: “A message could take 30 minutes to be sent from Stockholm to Gävle [some 200 km]”. This particular system, however, used 10 on/off shutters and we can thus translate that to 10 bits per symbol, etc.

For Morse code, there is often a words-per-minute count. In this case one has to assume an average symbol length and an average word length (in British it is 5.1 characters per word), the minute is also a bit vaguely defined since there is no standard delay between characters nor short/long beats on the key. In order to translate to bits per second, I have used what I have interpreted as best practice (various sources on the web).

Voice channels had a bandwidth of some 1 to 8 kHz in the early days and I have assumed 1 bps per Hz. Which is arguably

However, same holds for any system. Even if we say bps there might be additional overhead in terms of error correction coding, repetition, preambles, handshaking, etc.  on the line. I have reported the “raw” numbers and not cared to how much information as such is transferred. (With that said, how much information is there in a “Hi, how are you?” message?)

Notice that distances are not considered in the graph! One could argue that it is a bit unfair to compare apples and pears. I have focused a bit on the transatlantic cable as a use case. It illustrates the real challenges. The experimental Pbps optical fibres do not face the same type of challenges. Gauss first telegraphs were a couple of km. The Chappe telegraphs spanned 300 km and more. A longer cable would distort and attenuate the signal more aggressively and transmission speed would be lower. The very first transatlantic cable in the late 1850s (the notable red star at the bottom of the graph) only obtained a “few words per hour”! Horribly bad – but what an exceptional achievement?!

Curve-fitting does not work

As mentioned above – it is hard to get a polynomial interpolation to fit to the data in order to see trends. Exponential approximation do not seem to fit very well either. The R2 values are not impressive. It is quite clear that we instead should look at the graph and think in terms of distinct, paradigm-shifting scenarios. We have

  1. the arrival of the telegraph
  2. the introduction of Internet for the “masses”
  3. the arrival of the optical fibre
  4. satellite communication
  5. mobile phone
  6. etc

The telegraph (and telephony systems) shows a rather flat line from the 1820s to the 1930s. After the war, things start to roll. The launch of the SCORE satellite (1958) demonstrated communication across the globe – without cables. One could argue that Sputnik did the same, a year earlier, but it did not relay signals. The first transatlantic fiber cables were laid down in the 1980s.

Notable systems not mentioned in the graph

I did not include smoke signals nor the innovative time-coded pneumatic system used by the Greek in the fourth century.

I did not include the transmission speeds reported in the Star Trek movies (it is too far in the future and would stretch the graph too much). For the same reason I omitted the Star Wars across-the-galaxy-without-latency communication as it happened “a long time ago in a galaxy far, far away”.

The pi day … aka The Feigenbaum constant day

Ok, so the pi-day is up and running (March 14, i.e., 3-14). At approximately half past three today, some kind of pi would be served around the globe.

In an older post I found some alternative pi days for those who don’t like the date-system (Month-Day):

https://mixedsignal.wordpress.com/2013/07/04/heads-upe_pi/

and we found July 19 and July 22 as more “accurate” days for the pi – at least for us in Europe. The latter internationally acknowledged as the “Pi approximation day”. (Americans might claim March 1 as an approximation according to the principle Month/Day.)

So what else do we have? Is this it? Are there no other fancy constants that we could appreciate throughout the year?

Of course there is… forza some python and loop over the most commonly  (according to Wikipedia) used constants. Standard integers aside. A euro-date below is “Day/Month” and a US-date is a “Month/Day”. I have found the best-matching date in a least-square sense.

Notice the possible benefits of celebrating some/most constants twice a year if using both Euro and US date formats! I’ve however given preference to as early dates as possible for constants approximating to the same value for several dates. For example the interesting Legendre’s constant (= 1) which could be celebrated quite a few times throughout the year, but let’s stick to January 1.

It is also worth noticing  that the Feigenbaum constant approximation day could be celebrated today instead of pi.

  • Btw – what else than celebrating the imaginary number i on February 30.
Euro US Value Constant
22/07 03/01 3.14159265359 The pi day
19/07 11/04 2.71828182846 Eulers day
17/12 07/05 1.41421356237 Pythagoras day
19/11 12/07 1.73205080757 Theodorus day
20/09 09/04 2.2360679775 sqrt5-day
04/07 11/19 0.577215664902 Euler-Mascheroni constant
13/08 08/05 1.61803398875 Golden ratio
03/11 06/23 0.261497212848 Meissel-Mertens constant
02/07 07/25 0.280169499024 Bernsteins constant
03/10 07/23 0.303663002899 Gauss-Kuzmin-Wirsing constant
04/11 06/17 0.353236371855 Hafner-Sarnak-McCurley constant
01/02 01/02 0.5 Landaus constant
04/07 04/07 0.56714329041 Omega constant
05/08 05/08 0.624329988544 Golomb-Dickman constant
07/11 09/14 0.6434105462 Cahens constant
02/03 02/03 0.660161815847 Twin prime constant
02/03 02/03 0.662743419349 Laplace limit
07/10 07/10 0.70258 Embree-Trefethen constant
07/09 10/13 0.764223653589 Landau-Ramanujan constant
09/11 09/11 0.8093940205 Alladi-Grinstead constant
07/08 07/08 0.87058838 Bruns constant for prime quadruplets
11/12 11/12 0.915965594177 Catalans constant
01/01 01/01 1 Legendres constant
11/10 11/10 1.0986858055 Lengyels constant
09/08 09/08 1.13198824 Viswanaths constant
06/05 06/05 1.20205690316 Aperys constant
13/10 09/07 1.30357726903 Conways constant
13/10 09/07 1.30637788386 Mills constant
04/03 04/03 1.32471795724 Plastic constant
16/11 10/07 1.45136923488 Ramanujan-Soldner constant
16/11 10/07 1.45607494858 Backhouses constant
16/11 03/02 1.4670780794 Porters constant
17/11 11/07 1.5396007178 Liebs squareice constant
08/05 08/05 1.60669515242 Erdos-Borwein constant
17/10 12/07 1.70521114011 Nivens constant
19/10 11/06 1.9021605831 Bruns constant for twin primes
23/10 07/03 2.29558714939 Universal parabolic constant
05/02 05/02 2.5029078751 Feigenbaum constant
31/12 08/03 2.58498175958 Sierpinskis constant
27/10 08/03 2.68545200107 Khinchins constant
14/05 11/04 2.80777024203 Fransen-Robinson constant
23/07 10/03 3.27582291872 Levys constant
27/08 10/03 3.35988566624 Reciprocal Fibonacci constant
14/03 09/02 4.6692016091 Feigenbaum constant
30/2 2/30 i, sqrt(-1) The imaginary day (30/2!)

When will we bump into a transistor everywhere?

A while ago I made a comparison between Ostrogothia (Östergötland) and a silicon wafer. I wanted to put things into a graspable scale. If a transistor compares to an everyday object – how present will they be?

Maple-Martin, while digesting some Guinness at an Irish conference, suggested to take a look at the total number of available transistors on earth. According to Intel there were some 1.2e21 transistors worldwide last year(-ish).

 Let’s take some other dimensions into the picture:

  • On earth, there are 7 000 000 000 human beings (give or take some 100 millions), 7e9 
  • The earth’s equator is 40 000 km (4e7 m)
  • The earth’s total area is 510 million square kilometres, ie. 5.1e14 sqm
  • The channel length of an average transistor is assumed to be 100 nm
  • The channel width of an average transistor is assumed to be 100 nm
  • Each human consists of some 37e12 cells  [according to http://informahealthcare.com/doi/abs/10.3109/03014460.2013.807878 ]

Now, with these numbers at hand: Let us assume that we have too much time and we have somehow magically collect all the chips on earth and scrape off all transistors (that’s a big bag of chips). Then we decide to take a walk around the globe and put down some transistors here and there (perhaps to find our way back by picking them up on the way back?)

So if we neatly put them next to each other (think a long cascoded current source) in a long a row, we would have to walk

  • 1 200 000 000 000 000 000 000 pcs * 0.000 000 1 m/pcs = 120 000 000 000 000 m = 3 000 000 laps (!!!) around the globe.

Let’s assume we find that boring to just walk along the equator. If the transistors are 0.1 * 0.1 sq um big. They would then occupy 1e-14 = 1.2e21 * 1e-14 = 12e6 sq metres ~ 4000 * 3000 sq metres, or in non-American English: 4×3 sq km. Not that much (?)

If the transistors would be 600×600 sq um we would be able to cover the earth. 2010 – anyone?

We have 1.2e21 / 7e9 ~ 2e11 transistors per human being. That’s quite a potent processor! In an “ordinary” desktop computer there are some 5 billion transistors, i.e, 5e9 transistors. Which means that each human being is equipped, or has access to some 40 processors. (A phone, a computer, …)

Let’s bring the comparison further: Each human consists of some 37e12 cells which multiplies into a biomass of 37e12 * 7e9 = 270e21 human cells. Compare with 1.2e21 transistors – we are soon there! Soon we can assign one transistor to each human cell. 1984 – anyone?

[https://www.youtube.com/watch?v=WZEJ4OJTgg8]

PPT/ODP/PDF vs White/Blackboard

Following up on a facebook post and adding some more references and links as well as a poll for the fun of it . Also  noticing that there are 10 months since I posted here … other types of media have been used.

So, the question was about what we prefer to listen to. What type of performance do we prefer in the lecture hall – powerpoint or whiteboard? Personally, I do not feel very comfortable using powerpoint [PDF/ODP/beamer/whatever] to present nor listen to. The lectures I mostly enjoy are either the ones with just a few “simple” slides, or simpler annotations. For example

or why not the great lectures by

where you can find lectures by Prof. Adams or why not the great lectures by

(Yes, I admit that this is a “meta-discussion” in the sense that we watch someone lecture on a youtube channel thus making it more or less a powerpoint presentation – but I think you know what I mean).

I would also like to highlight the

that display a method that is somewhat in-between. A static “slide” (landscape?) but a detailed walk-through of the stuff on the board. Some of his “wild” [pun intended] ideas aside, it is comfortable to listen to him.

Back to powerpoint (or PDF or ODP) [copy from the facebook pages]: What especially annoys me are those presenters who read out loud the text displayed on the screen. The audience has already read the whole page twice before the presenter reaches the end of first sentence. And mostly, they have already understood the contents before presenter starts to mumble and desperately tries to remember what they’ve written three years earlier.

Too many times I have had lectures where the students have fallen asleep – more or less. It does not really matter if I distribute material in advance.  Yes, I know it is also my fault – I should probably prepare better slides and present them better. Perhaps I make the errors mentioned above.

But taking the pen and massaging the text and moving across the whiteboard is more satisfying. Making some errors now and then and erasing and rewriting after interaction from and with the audicence makes the presentation more live.

The downside is of course efficiency – which is important! – there is limited time slot in the teacher’s schedule and in the students’ schedules. Watching a professor slowly writing the formulae on the board could sometimes be as interesting as watching paint dry.

The combination of slides and board? Well, there is a risk of interupting the flow. There is no natural way of conetext-switching. Displaying some complex graphs? Equations? Well, yes, perhaps – but reproducing them line-by-line on the board is also part of the explanation procedure.

I am thinking of this graph, where yellow displays the “match” between entertainment and learning level. Doing the repetitive stuff, over and over again, is perhaps not that fun, but learning is better IMO. Think of it as a movie with Schwarzenegger vs a documentary with Attenborough vs peeling 200 kg of potatoe. (Well…) There are differences between being entertained, interacting and just performing repetitive patterns.  Can we fill the white boxes with yellow knowledge?

 

2017-03-05