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Television has been around for a long time, but what we point to and call a TV these days is a completely different object from what consumers first fell in love with. This video of RCA factory tours from the 1950s drives home how foreign the old designs are to modern eyes.
https://www.youtube.com/watch?v=lxQS58t39_U //
The next youtube video that came up is a great watch also if you’re interested in the cathode ray tube alone details: https://www.youtube.com/watch?v=qp6tNaUvfNI
For those of us who lived through the Cold War, there’s still an air of mystery as to what it was like on the Communist side. As Uncle Sam’s F-111s cruised slowly in to land above our heads in our sleepy Oxfordshire village it was at the same time very real and immediate, yet also distant. Other than being told how fortunate we were to be capitalists while those on the communist side lived lives of mindless drudgery under their authoritarian boot heel, we knew nothing of the people on the other side of the Wall, and God knows what they were told about us. It’s thus interesting on more than one level to find a promotional film from the mid 1970s showcasing VEB Fernsehgerätewerk Stassfurt (German, Anglophones will need to enable subtitle translation), the factory which produced televisions for East Germans. It provides a pretty comprehensive look at how a 1970s TV set was made, gives us a gateway into the East German consumer electronics business as a whole, and a chance to see how the East Germany preferred to see itself.
Making an oscilloscope is relatively easy, while making a very fast oscilloscope is hard. There’s a trick that converts a mundane instrument into a very fast one, it’s been around since the 1950s, and [CuriousMarc] has a video explaining it with an instrument from the 1960s. The diode sampler is the electronic equivalent of a stroboscope, capturing parts of multiple cycle of a waveform to give a much-slowed-down representation of it on the screen. How it works is both extremely simple, and also exceptionally clever as some genius-level high-speed tricks are used to push it to the limit. We’ve put the video below the break.
The first digital logic gate built from vacuum tubes appears to have been invented by Bruno Rossi in 1930. Rossi, an Italian physicist studying cosmic rays and radioactivity, was not working on computing equipment but rather sought to detect near-simultaneous events from multiple Geiger-Müller tubes, His Rossi coincidence circuit was an n-input AND gate which identified coincident pulses from multiple detectors with a time resolution of one millisecond.
With an inverting output, this circuit would be a NAND gate 1, from which any Boolean function can be computed and flip-flops constructed as a data storage element.
After his outpour of encouragement, I was motivated to create a solution, no matter how hard. I had a rough idea in my mind, but it was going to be tough oh who am I kidding, it’s five buttons connected to a microcontroller, it would take two minutes.
It took four hours. Close enough.
The hardware
Behold.
As I said, the hardware is simple enough: Just a microcontroller and five keyboard switches wired to five of its input pins. Since this build //
Deciding which key presses would correspond to which characters was the hardest part, but also the most creative. Since this is a brand-new keyboard layout, I would not be beholden to the mistakes of the past. No more jamming typewriters for me, no more bigrams, I would have free rein to perform extensive research and decide what the optimal correspondence would be for my layout.
I decided that that was too much work, and that I’d just fall back to the good old etaoin shrdlu. I found the character frequencies in the English language, and made sure that each of the five most frequently used characters (the spacebar, “e”, “t”, etc) had its own key. After that, the next most frequent characters got a double press (the thumb plus one of the four others). Then came double presses between the other keys, then triple presses, etc.
The Zyklus' MIDI Performance System allows you to record sequences: 99 polyphonic single-channel sequences, to be exact. These can be organised into groups of 12 sequences which are known as Configurations, of which the MPS allows you to store 24 in its internal memory. Once you've recorded a few sequences and organised them into a Configuration, you can "play" them from a MIDI keyboard and from dedicated front-panel Control buttons. These actions can in turn be recorded into one of 12 Performances. The important point to bear in mind is that the MPS's sequences are totally independent of one another. You can treat the MPS as a 12-track sequencer, but that's only one of countless options available to you, and it's really missing the point.
The Zyklus MIDI PERFORMANCE SYSTEM is a MIDI equipment controller designed to provide an unprecedented level of musical control. It achieves this by allowing the musician to interact with previously recorded MIDI data such as sequences so that complex music can be build up in real time. In a typical setup, the MIDI PERFORMANCE SYSTEM would be used in conjunction with a MIDI master keyboard or keyboard synthesizer, plus up to 64 slave MIDI devices - synthesizers, expanders, drum machines, MIDI-equiped signal processors, etc.
The MIDI PERFORMANCE SYSTEM can be thought of a collection of sequencers, MIDI control boxes and MIDI effects units integrated into a single system. This system is designed so that it can be "played" like a musical instrument in its own right. At its most basic level it is rather like 12 polyphonic sequencers, each of which can be run at any transposition or set of simultaneous transpositions independently of the others, simply by pressing a note or chord on the MIDI control keyboard. 99 different sequences can be stored in each memory bank, of which any 12 can be assigned to the front panel for immediate access together with related control information. These sequences need not consist of repeating musical phrases. They could be single chords, short fast runs which end on held chords, segments of control data such as MIDI program changes, the synthesisers/drum part for an entire song, etc.
In addition to keyboard triggering, sequences can be triggered from a footswitch, an external trigger source or directly from the front panel. The panel controls consist of 40 keys mostly with LED indicator, plus a encoder wheel used for tempo control, editing functions, menu selection, etc. User information is provided by a 40 x 2 backlit LCD with externally adjustable brightness and contrast.
You all will know my motives much better after reading Bill Marshall's own informative article about the issue:
Twenty Five Years Later… (in case you don't have Word program, you could use wordpad)
First, let me begin with my own impression:
Do you rememeber when Yamaha DX-7 came the first time? At the time it was totally new thing, something that you never heard before and there wasn't anything else to compare it's features, so basically you had to hear and see the device yourself before you could understand, experience and see the potential of it.
Could you possibly imagine what the world would have been if the DX7 would have ended up as a flop product that no-one could understand? What if only handful DX7 were produced and then disappeared from the public? Perhaps in such world we would have seen much wider and more perfect analog instruments, with all the features finished to their maximum potential. Perhaps Yamaha would have brought their CS-80 to next level and continued their incredible legacy of ultimate player's and performer's keyboard that acts like real instrument. Even though I'm not the correct generation, but I think, DX7 as a flop product actually could have happened. No-one knew how to program it and there was no much of live controls either. What if Yamaha wasn't able to provide their large palette of presets and users were left with basic "Init" waveforms? Would that been enough make it finito?
I can imagine that, because I have already "seen it". I have seen that world in form of Zyklus MPS-1 - Midi Performance System. At the time, what DX7 was for synthesizers, MPS-1 was for sequencers. MPS-1 represented entirely new way of thinking... a totally new approach sequencing and making music. People couldn't understand it. Even today with all these groove boxes and other things, people can't understand what MPS-1 is capable, mainly because there never were anything else to compare. I can only imagine what the world would have been if MPS-1 could have made even moderate level of success. As Bill said, he expected someone else to continue his visions and innovations but the industry took totally different direction and totally abandoned these all. Even today, the modern industry still makes the usual safe product that will sell for sure, a new reverb or new compressor... or another "studio-in-the-box" gadget.
The problem is that even in this very modern world where technological progression is unbelieveable when comparing to 1988, still we don't see products that can act as a tool for encouraging the actual creative process of creating music. Everything is only about recording, editing and composing music in traditional way but nothing to encourage you to experiment and try new things.
If MPS-1 is still alien in this highly advanced modern world, just imagine it in 1988. Even today people expect easy "analogies". When it comes to sequencers, people still expect them to work like traditional multitrack tape recorders. I surely will have difficulties to describe the potential of MPS-1 without having chances to actually show the process how it works. The situation reminds me of John Cage and his methods. You need to show people that music performance could include weird things like pouring water to bathtub... any sound could be music too.
The Vacuum Tube’s Forgotten Rival
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FEATURE
HISTORY OF TECHNOLOGY
THE VACUUM TUBE’S FORGOTTEN RIVAL
Magnetic amplifiers, the alt-tech of the Third Reich, lasted into the Internet era
KEN SHIRRIFF
27 MAR 202212 MIN READ
A photo of an older woman in front of an early generation computer.
Magnetic amplifiers were used in the Univac Solid State, shown here being operated in 1961 by pioneering computer scientist Grace Hopper. COMPUTER HISTORY MUSEUM
DURING THE SECOND World War, the German military developed what were at the time some very sophisticated technologies, including the V-2 rockets it used to rain destruction on London. Yet the V-2, along with much other German military hardware, depended on an obscure and seemingly antiquated component you’ve probably never heard of, something called the magnetic amplifier or mag amp.
In the United States, mag amps had long been considered obsolete—“too slow, cumbersome, and inefficient to be taken seriously,” according to one source. So U.S. military-electronics experts of that era were baffled by the extensive German use of this device, which they first learned about from interrogating German prisoners of war. What did the Third Reich’s engineers know that had eluded the Americans?
After the war, U.S. intelligence officers scoured Germany for useful scientific and technical information. Four hundred experts sifted through billions of pages of documents and shipped 3.5 million microfilmed pages back to the United States, along with almost 200 tonnes of German industrial equipment. Among this mass of information and equipment was the secret of Germany’s magnetic amplifiers: metal alloys that made these devices compact, efficient, and reliable.
U.S. engineers were soon able to reproduce those alloys. As a result, the 1950s and ’60s saw a renaissance for magnetic amplifiers, during which they were used extensively in the military, aerospace, and other industries. They even appeared in some early solid-state digital computers before giving way entirely to transistors. Nowadays, that history is all but forgotten. So here I’ll offer the little-known story of the mag amp.
An amplifier, by definition, is a device that allows a small signal to control a larger one. An old-fashioned triode vacuum tube does that using a voltage applied to its grid electrode. A modern field-effect transistor does it using a voltage applied to its gate. The mag amp exercises control electromagnetically.
A photo of a rocket on a launcher with trees in the background. A photo of a man sitting at an early computer next to a typewriter.A photo of two men sitting at a terminal in front of an early computer.Magnetic amplifiers were used for a variety of applications, including in the infamous V-2 rockets [top] that the Germany military employed during the Second World War and in the Magstec computer [middle], completed in 1956. The British Elliot 803 computer of 1961 [bottom] used related core-transistor logic. FROM TOP: FOX PHOTOS/GETTY IMAGES; REMINGTON RAND UNIVAC; SMITH ARCHIVE/ALAMY
To understand how it works, first consider a simple inductor, say, a wire coiled around an iron rod. Such an inductor will tend to block the flow of alternating current through the wire. That’s because when current flows, the coil creates an alternating magnetic field, concentrated in the iron rod. And that varying magnetic field induces voltages in the wire that act to oppose the alternating current that created the field in the first place.
If such an inductor carries a lot of current, the rod can reach a state called saturation, whereby the iron cannot become any more magnetized than it already is. When that happens, current passes through the coil virtually unimpeded. Saturation is usually undesirable, but the mag amp exploits this effect.
Physically, a magnetic amplifier is built around a metallic core of material that can easily be saturated, typically a ring or square loop with a wire wrapped around it. A second wire also wrapped around the core forms a control winding. The control winding includes many turns of wire, so by passing a relatively small direct current through it, the iron core can be forced into or out of saturation.
The mag amp thus behaves like a switch: When saturated, it lets the AC current in its main winding pass unimpeded; when unsaturated, it blocks that current. Amplification occurs because a relatively small DC control current can modify a much larger AC load current.
The history of magnetic amplifiers starts in the United States with some patents filed in 1901. By 1916, large magnetic amplifiers were being used for transatlantic radio telephony, carried out with an invention called an Alexanderson alternator, which produced a high-power, high-frequency alternating current for the radio transmitter. A magnetic amplifier modulated the output of the transmitter according to the strength of the voice signal to be transmitted.
One Navy training manual of 1951 explained magnetic amplifiers in detail—although with a defensive attitude about their history.
In the 1920s, improvements in vacuum tubes made this combination of Alexanderson alternator and magnetic amplifier obsolete. This left the magnetic amplifier to play only minor roles, such as for light dimmers in theaters.
Germany’s later successes with magnetic amplifiers hinged largely on the development of advanced magnetic alloys. A magnetic amplifier built from these materials switched sharply between the on and off states, providing greater control and efficiency. These materials were, however, exquisitely sensitive to impurities, variations in crystal size and orientation, and even mechanical stress. So they required an exacting manufacturing process.
The best-performing German material, developed in 1943, was called Permenorm 5000-Z. It was an extremely pure fifty/fifty nickel-iron alloy, melted under a partial vacuum. The metal was then cold-rolled as thin as paper and wound around a nonmagnetic form. The result resembled a roll of tape, with thin Permenorm metal making up the tape. After winding, the module was annealed in hydrogen at 1,100 °C for 2 hours and then rapidly cooled. This process oriented the metal crystals so that they behaved like one large crystal with uniform properties. Only after this was done were wires wrapped around the core.
By 1948, scientists at the U.S. Naval Ordnance Laboratory, in Maryland, had figured out how to manufacture this alloy, which was soon marketed by an outfit called Arnold Engineering Co. under the name Deltamax. The arrival of this magnetic material in the United States led to renewed enthusiasm for magnetic amplifiers, which tolerated extreme conditions and didn’t burn out like vacuum tubes. Mag amps thus found many applications in demanding environments, especially military, space, and industrial control.
During the 1950s, the U.S. military was using magnetic amplifiers in automatic pilots, fire-control apparatus, servo systems, radar and sonar equipment, the RIM-2 Terrier surface-to-air missile, and many other roles. One Navy training manual of 1951 explained magnetic amplifiers in detail—although with a defensive attitude about their history: “Many engineers are under the impression that the Germans invented the magnetic amplifier; actually it is an American invention. The Germans simply took our comparatively crude device, improved the efficiency and response time, reduced weight and bulk, broadened its field of application, and handed it back to us.”
The U.S. space program also made extensive use of magnetic amplifiers because of their reliability. For example, the Redstone rocket, which launched Alan Shepard into space in 1961, used magnetic amplifiers. In the Apollo missions to the moon during the 1960s and ’70s, magnetic amplifiers controlled power supplies and fan blowers. Satellites of that era used magnetic amplifiers for signal conditioning, for current sensing and limiting, and for telemetry. Even the space shuttle used magnetic amplifiers to dim its fluorescent lights.
The image shows a Redstone rocket at the launch pad, with three space-suit-wearing astronauts in the foreground.Magnetic amplifiers were also used in Redstone rockets, like the one shown here behind astronauts John Glenn, Virgil Grissom, and Alan Shepard.UNIVERSAL IMAGES GROUP/GETTY IMAGES
Magnetic amplifiers also found heavy use in industrial control and automation, with many products containing them being marketed under such brand names as General Electric’s Amplistat, CGS Laboratories’ Increductor, Westinghouse’s Cypak (cybernetic package), and Librascope’s Unidec (universal decision element).
The magnetic materials developed in Germany during the Second World War had their largest postwar impact of all, though, on the computer industry. In the late 1940s, researchers immediately recognized the ability of the new magnetic materials to store data. A circular magnetic core could be magnetized counterclockwise or clockwise, storing a 0 or a 1. Having what’s known as a rectangular hysteresis loop ensured that the material would stay solidly magnetized in one of these states after power was removed.
Researchers soon constructed what was called core memory from dense grids of magnetic cores. And these technologists soon switched from using wound-metal cores to cores made from ferrite, a ceramic material containing iron oxide. By the mid-1960s, ferrite cores were stamped out by the billions as manufacturing costs dropped to a fraction of a cent per core.
But core memory is not the only place where magnetic materials had an influence on early digital computers. The first generation of those machines, starting in the 1940s, computed using vacuum tubes. These were replaced in the late 1950s with a second generation based on transistors, followed by third-generation computers built from integrated circuits.
Transistors weren’t an obvious winner for early computers, and many other alternatives were developed, including magnetic amplifiers.
But technological progress in computing wasn’t, in fact, this linear. Early transistors weren’t an obvious winner, and many other alternatives were developed. Magnetic amplifiers were one of several largely forgotten computing technologies that fell between the generations.
That’s because researchers in the early 1950s realized that magnetic cores could not only hold data but also perform logic functions. By putting multiple windings around a core, inputs could be combined. A winding in the opposite direction could inhibit other inputs, for example. Complex logic circuits could be implemented by connecting such cores together in various arrangements. //
Octopart is the easiest search engine for electronic parts.
Search across hundreds of distributors
and thousands of manufacturers.
If you lack a shortwave radio and a dig around all your family’s junk hasn’t turned up a relic from decades past, then the simplest way to get one is of course to buy one. AliExpress is full of “world band” radios starting from somewhere under $20, and if you don’t mind waiting for shipping from China then it’s the path of least resistance.
But there’s the problem, international events are moving fast and there might not be the luxury of waiting three weeks, or even for that matter of being able to order one at all in a warzone. How can you make one? //
geocrasher says:
March 17, 2022 at 8:56 am
If anybody would like to build a Direct Conversion receiver from scratch, I have documented a design and build on my site. It covers the theory of operation as well as construction techniques, and uses the si5351a as an oscillator with an Arduino for control. Has to be heard to be appreciated :)
https://miscdotgeek.com/building-direct-conversion-receiver-part-1/
Aluminum doesn’t solder well, and that’s because of the oxide layer that rapidly forms on the surface. [Ted]’s solution is to scour the aluminum with some mineral oil. The goal is to scrape away the oxide layer on the aluminum’s surface, while the mineral oil’s coating action prevents a new oxide layer from immediately re-forming.
After this prep, [Ted] uses a hot soldering iron and a blob of solder, heating it until it sticks. A fair bit of heat is usually needed, because aluminum is a great heat conductor and tends to be lot thicker than a typical copper ground plane. But once the aluminum is successfully tinned, just about anything can be soldered to it in a familiar way.
[Ted] does caution that mineral oil can ignite around 260 °C (500 °F), so a plan should be in place when using this method, just in case the small amount of oil catches fire.
audio isolator or data diode (one way data -- rs232)
Introduction
Yes, yes...it's yet another set of instructions for constructing your very own digital coaxial to optical converter. First off, why you would need such a device - you have a sound source with a coax digital output, and a digital recorder that accepts optical input (in most cases, everyone's favorite - the minidisc recorder). Total cost for this project will run $25-$30.
Now, does recording digitally make a difference? I would say that while analog recording sounds fine for general use, digital recording is very nice for devices where you would be better off bypassing the DACs. Digital to analog converters do exactly as they say - take digital values and produce a proportional analog voltage to feed your speakers/headphones. //
ThunderScope, the Open Source Software-Defined Oscilloscope, Is Coming to Crowd Supply - Hackster.io
Up to 350 MHz analog bandwidth with 1 GaSa/s sample rate streamed to a PC at 1 Gb/s. //
ThunderScope comes in an unassuming box that is just large enough to house 4 BNC connectors, a compensation output, four fully-functional front-end stages, an ADC, and an Artix-7 FPGA to capture the data and transfer it to the PC.
[Marco] looks at a lot of meters. However, he considers the HP3458A the best even though they were introduced more than 30 years earlier in 1989. Someone donated one to [Marco] but it presented some error messages on startup and exhibited erratic behavior, so he had some repairs to do.
The error codes hinted there were issues with the multislope analog to digital converter and that’s what sets the meter apart, according to [Marco]. The meter has 8.5 digits, so a normal conversion stage won’t cut it.
A consortium of companies including Intel, Motorola, and AMD began studying EUV as the next step in lithography in the 1990s. ASML joined in 1999, and as a leading maker of lithography technology, sought to develop the first EUV machines. Extreme ultraviolet lithography, or EUV for short, allows a much shorter wavelength of light (13.5 nanometers) to be used, compared with deep ultraviolet, the previous lithographic method (193 nanometers).
But it has taken decades to iron out the engineering challenges. Generating EUV light is itself a big problem. ASML’s method involves directing high-power lasers at droplets of tin 50,000 times per second to generate high-intensity light. Lenses absorb EUV frequencies, so the system uses incredibly precise mirrors coated with special materials instead. Inside ASML’s machine, EUV light bounces off several mirrors before passing through the reticle, which moves with nanoscale precision to align the layers on the silicon. //
ASML’s new machine introduces an additional trick to produce smaller features on a chip: a larger numerical aperture, which increases the resolution of imaging by allowing light to travel through the optics at different angles. This requires significantly larger mirrors and new software and hardware to precisely control the components. ASML’s current generation of EUV machines can create chips with a resolution of 13 nanometers. The next generation will use High-NA to craft features 8 nanometers in size. //
Demand for faster chips is hardly likely to go down. Mark Lundstrom, a professor at Purdue who began working in the chip industry in the 1970s, wrote an article for Science magazine in 2003 that predicted Moore’s law would run into physical limits within a decade. “In my career, multiple times we thought ‘OK, this is the end,’” he says. “But there's no danger at all that things will slow down in 10 years. We'll just have to do it differently.”
Lundstrom remembers visiting his first microchip conference in 1975. “There was this fellow named Gordon Moore giving a talk,” he recalls. “He was well known within the technical community, but nobody else knew him.”
“And I remember the talk that he gave,” Lundstrom adds. “He said, ‘We will soon be able to place 10,000 transistors on a chip.’ And he added, 'What could anyone possibly do with 10,000 transistors on a chip?’”
Hackaday Prize 2021 Finalist ThunderScope is doing exactly that. [Aleska] is building a modular open source PC-connected oscilloscope aiming at four channels and a cool 100 MHz bandwidth with a low budget. The detailed project logs, showing how he is learning about ‘scope technology on-the-fly is a fascinating look into the mind of an engineer as he navigates the ups and downs of a reasonably complicated build.
We like how [Aleska] has realised early on, that keeping the project private and only releasing it when “I’m done” actually impedes progress, when you could open source from the beginning, log progress and get great feedback right from the start. All those obvious mistakes and poor design choices get caught and fixed before committing to hardware. Just think of all the time saved. Now this is an attitude to cultivate!
Spec revision № 1.0
Time Card is the heart of the Open Time Server Project.
This spec can be accessed using http://www.timingcard.com
Time Master is a critical part of a PTP enabled network. It provides accurate time via GNSS while maintains the accuracy in case of GNSS failure via a high stability (and holdover) oscillator such as an atomic clock. Exisiting products in the market are often closed sourced an far from sufficient features. The Time Card project presents an open source solution via a PCIe card.
Form Factor
- Standard PCIe Stand-up Card
- Single Slot - Passive Cooling Solution
....
Repository content
- Bill of Materials (parts from Digikey)
- Schematic and PCB of the time card
- Driver (Kernel Module) CentOS 8
- CAD files for the custom PCIe bracket
Where can I get one?
You have all necessary source code, BOM, Gerber files and binaries to build it youself. However, we are currently working with several suppliers and will have their contact info soon available to allow you to puchase an out-of-the-box ready Time Card.
What is SWaP-C?
Size, Weight, Power and Cost.
Multiplied together, they produce a number that limits the possible use cases the higher it is, particularly in application areas where these factors count:
- When payload is measured to the gram
- When you don’t have an inch to space
- When power needs to be conserved
- When cost is critical
The Spectratime mRO-50 is a breakthrough low SWaP-C Miniaturized Rubidium Oscillator designed to meet the latest commercial, military and aerospace requirements where time stability and power consumption are critical.
It provides a one day holdover below 1µs and a retrace below 1 x 10-10 in a form factor (50.8 x 50.8 x 19.5mm) that takes up only 51 cc of volume (about one-third of the volume compared to standard rubidiums) and consumes only 0.45W of power, or about ten times less than existing solutions with similar capabilities.
The Spectratime mRO-50 Miniaturized Rubidium Oscillator provides accurate frequency and precise time synchronization to mobile applications, such as military radio-pack systems in GNSS denied environments. Its wide-ranging operating temperature of -10°C to 60°C is also ideal for UAVs and underwater applications.
Megohmmeter Model 6529
Low Cost, Hand-held Multimeter/Megohmmeter
Model 6529 is a low cost 1000V hand-held instrument that offers Multimeter functions as well as Megohmmeter functions. This model is created for the commercial, industrial and contractor markets and is simple to use. It's priced at a point tailored to contractors and independent electricians that need to check the quality of insulation as well as perform basic electrical measurements.
True Megohmmeter®
It is a True Megohmmeter® in compliance with IEC 61010 and is designed with features and functions for use in the field:
lightweight
compact
rugged
easy to handle, even when wearing gloves.Its construction and interface is intended to simplify use. An intuitive pass/fail indication offering a blue/red backlight makes it very easy to identify defective conditions.
Automatic Test Inhibit for Safety
It includes an automatic test inhibit if connected to a live circuit as well as automatic discharge at the completion of the test.
Parabolic reflector antenna gain can be calculated from some simple formulas or equations, and the practical factors affecting the 'dish' antenna gain.