Three Milestones Get Their Due

The development and commercial introduction of the HP-35 and an early wireless development were honored

6 May 2009

In April and May at sites on three continents, the IEEE commemorated noteworthy advances in technology with ceremonies recognizing them as IEEE Milestones in Electrical Engineering and Computing.

One of the achievements, an early advance in wireless communications, bridged two continents. On 15 April 1929, a longwave radio transmitting station in the tiny Japanese village of Yosami, near Nagoya, successfully sent messages to Warsaw. The station was built when Japan—in the aftermath of World War I—realized it could no longer rely on wireline networks operated by foreign companies for commercial and diplomatic communications between itself and Europe.

To be able to ferry signals across Asia and into Europe, the government commissioned high-frequency generators known as machine senders. They produced 5.814-kilohertz waves at an output power of 500 kilowatts. A frequency-multiplying transformer stepped up the frequency to the 17.442 kHz over which signals were broadcast. The transmitter—which comprised a 920-kW induction motor, an 860-kW dc generator, a 730-kW dc motor, and an induction alternator connected in series—kept the frequency of the carrier waves constant by linking the alternator and generator via a feedback loop that maintained their rotating speeds.

Advanced as it was, the giant radio facility—with its 16 antenna wires set atop eight 250-meter-high, 300-ton towers—was quickly eclipsed by shortwave radio and rendered obsolete almost from the moment it was completed. By the early 1930s, shortwave radio, which amateur radio operators had been feverishly refining for years, had reached the point where its broadcasts could span the same distances using a fraction of the power needed to propagate longwaves. Yosami was relegated to the role of a backup used only in the winter when instability in the ionosphere made shortwave transmissions less reliable.

But the station won a reprieve from the dustbin when it was discovered that longwave frequencies could be picked up by antennas located as deep as 20 meters under water. That made the station ideal for communication with submarines. The Japanese Navy took advantage of Yosami’s longwave generation during World War II. The United States, which took over Japan’s military facilities after the war, used it to communicate with its own subs from the 1950s through 1993.

The station was dismantled and moved to a nearby site in 1996. The IEEE Milestone plaque will be placed at the transmitter’s current home, which is part of a museum dedicated to the achievement. The plaque will inform museum visitors that IEEE has recognized Yosami because the station “established the first wireless communications between Japan and Europe” and because of its five-decade-long second life as a node for communicating with submarines.

TALE OF THE TELEGRAPH
Ask most U.S. schoolchildren to name the inventor of the telegraph and, as if by reflex, they probably would say Samuel F.B. Morse. But Russian schoolchildren would name Pavel Lvovitch Schilling.

Although Morse played an important role in bringing forth near-instantaneous long-distance communication, his telegraph of 1844 was merely a refinement of existing models. One such telegraph was Schilling’s, which was nominated for IEEE milestone status by the IEEE Russia Northwest Section. As early as 1828, Schilling was tinkering with a device (based on an idea cooked up by André-Marie Ampère, the noted physicist and mathematician credited as one of the discoverers of electromagnetism) that could transfer electric signals along a wire and generate messages using electric currents to manipulate a magnetic needle.

The main improvements Schilling introduced included a simplification of Ampère’s idea that eliminated some of the wiring; an indicator system with 64 possible combinations, enough to assign a separate code to each letter, number, operand, and special sign; and a book that listed the codes.

By 1830, he had demonstrated the device numerous times, sending messages from one room to another and over short distances around St. Petersburg. In 1836, he connected two government buildings 5 km apart via a cable that at one point lay at the bottom of a canal.

The Russian scientist never marketed his invention nor even bothered to patent it. Although later devices were undoubtedly its progeny, credit eluded him. For example, in the descriptions accompanying their 1837 patent application, W.F. Cook and Charles Wheatstone attributed Schilling’s ideas to the chairman of a scientific congress where Schilling had demonstrated his device two years earlier.

Morse’s better-known telegraph was similar to Schilling’s. The important difference was that the Russian’s device displayed visual code marks that the operator had to rapidly decipher and transcribe as the signal came through, whereas the American’s created a permanent record by marking dots and dashes on paper.

Schilling’s achievement has been celebrated in Russia with honors including a postage stamp bearing his likeness.

Two plaques—one in Russian and another in English—are to be unveiled on 18 May at the Central Museum of Communications in St. Petersburg, where Schilling’s original telegraph is on display. The plaques honor his demonstrations in St. Petersburg and abroad—which they say provided “an impetus to scientists in different countries and influenced the invention of more advanced electromagnetic telegraphs.”

PROCESSORS IN YOUR POCKET
A ceremonial plaque was unveiled on 14 April at Hewlett-Packard’s laboratories in Palo Alto, Calif., to commemorate the development and commercial introduction in 1972 of the HP-35, the world’s first full-function scientific calculator small enough to fit in a shirt pocket. But perhaps a ceremonial chalk outline in the shape of a slide rule also should have been drawn nearby to indicate that the labs were the place where the death knell was sounded for that centuries-old device.

Immediately after the 1968 introduction of the HP-9100, the company’s first programmable desktop calculator, Bill Hewlett presented his engineers with an even tougher challenge: make a portable version that would perform calculations 10 times as fast, in a package one tenth the size, and cost one tenth the 9100’s US $4900 retail price.

Starting with a set of rough sketches based on the dimensions of a pack of cigarettes, H-P’s industrial designers came up with a hardened plastic case that passed muster with Hewlett because it easily slipped into his shirt pocket. Then came the hard part. A year and four months later—roughly half the company’s normal product development cycle—the HP-35 was to go into production. Inside that tight development window, engineers faced several problems.

The team had to come up with a logic scheme that could perform complex operations in less than a second. But the chips doing the work had to fit inside the 14.7-by-8.1-by-3.3-centimeter case. Bipolar transistors capable of replicating the logarithmic and trigonometric functions of a slide rule were too large and drew too much power. The nickel-cadmium battery pack being proposed wouldn’t last long enough. Metal oxide semiconductors held the promise of being small, fast, and miserly enough with power, but were not sufficiently developed in 1968 to be relied upon. But by 1970, they had advanced to the point that H-P engineers settled on a PMOS binary coded decimal (BCD) adder with 13-digit-long words. Thirteen digits and a plus or minus sign equated to 56 bits.

Meanwhile, the developers were innovating in other areas including digital displays and keypad design. They attached a molded plastic lens to a bank of LEDs that magnified the digits without distorting their shape, and they devised a keypad design still in use today.

Within a year of the HP-35’s March 1972 introduction, engineers and students had bought more than 100 000 of the $395 devices. The handwriting was on the wall, and in another couple of years or so the scientific calculator had replaced the venerable slide rule.

The IEEE Milestone plaque will be displayed in the lobby of the building where much of the design work for the electronic slide rule was carried out.

 

 

 

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