Germany has long been associated with the type of precision engineering that has produced high-quality cameras, fast automobiles, and even the Autobahn roadway to accommodate those higher driving speeds. But this proud country is also home to one of the leading and most innovative test-andmeasurement companies in the world: Rohde & Schwarz GmbH. From its humble beginnings, the firm has grown through the years to now achieve its 75th anniversary, a mark shared by few manufacturers anywhere, let alone companies serving the RF/ microwave industry.

The year 1932 was noteworthy for numerous events. For one, the Graf Zeppelin--the "lighter-than-air" flying ship--began a regular route between Germany and South America. Amelia Earhart flew from the United States to Northern Ireland in 14 hours and 54 minutes. New York City's Radio City Music Hall opened its doors. Amidst these historical occurrences, Dr. Lothar Rohde and Dr. Hermann Schwarz received their doctorates. Few would have thought that the company they were about to found would become a world leader in RF and microwave test and measurement equipment, defense electronics, and broadcast equipment, with annual sales of more than $2.1 billion (Fig. 1).

Armed with their Ph.D.s, the two engineers (Fig. 2) went to work at Germany's University of Jena, where they soon met Hans Handrek, an engineer at an insulator manufacturer (the Hermsdorf- Schomburg-Isolatoren-Gesellschaft or "Hescho"). Handrek's firm was sampling new ceramic materials for radio engineering to numerous institutions throughout Germany and beyond, but all reported imprecise loss-factor measurements. To help Handrek, the two young engineers developed a test protocol that provided precise test data quickly. Their efforts resulted in the first "Rohde & Schwarz measurement product even before the company was actually formed."

Having met this challenge, the two engineers decided to set out in business and set up shop in Munich under the formidable name "Physikalisch- Technisches Entwicklungslabor Dr. L. Rohde und Dr. H. Schwarz" (also known as "PTE"). Their "headquarters" (Fig. 3) was typical of so many fledgling companies: a 1200-square-foot apartment located in Munich's Old Town district and equipped with second-hand office furniture and workshop equipment.

At the time, RF/microwave engineers had few choices for test instruments. Measurement equipment was usually assembled as needed, and such equipment tended to be difficult to use and imprecise. Seeing this shortcoming as a potential opportunity, the two engineers decided to concentrate on developing instruments that could be used without special training. Their small lab grew quickly and in 1934 PTE hired its first engineer and leased a second workshop when its needs outgrew the available space. Rohde and Schwarz also realized they needed a new business model, because many customers wanted instruments rather than just instrument designs, so PTE began to focus on manufacturing. Schwarz later recalled that "it wasn't until 1936 that we were manufacturing test instruments in lots of up to 50 units. But we still did everything by hand."

Adds Richard Leonhardt, who joined the company in 1936 and who later served as head of the engineering division: "To develop new instruments in the early years, we first had to invent the technology needed to build them. Test equipment was available for highvoltage or direct-current technologies, but there was nothing for RF technology. In fact, technical literature at the time described 250 different test methods for RF technologies, but there wasn't a single instrument available for any of them. So you had to come up with something yourself, to be a specialist, a T&M artist.' Rohde & Schwarz always tried to make these T&M artists' unnecessary."

In 1937, the company moved its 35 employees to a former bread factory near the Munich East Train Station. It was a bold step because the price of the building was about twice the value of its assets, but by 1938 the company was already selling 100 different products and by 1943 had grown to 600 employees. Some exceptional instruments emerged during the period, including the WIP interference wavemeter that was sold throughout the world for more than two decades (Fig. 4). By the standards of the day, the WIP had a broad range of measurement frequencies, covering wavelengths from 6 to 3000 m.

In 1938, PTE manufactured the world's first portable crystal clock, which brought the company recognition beyond Germany and could be used as a frequency generator standard since its accuracy was +/- 0.004 s per day. It was also comparatively lightweight, at only 100 lb. including its rack, when competitive models were housed in large cabinets and weighed much more. The clock was well received as a frequency standard for test shops and laboratories.

In 1942, the company received a large order for radio test receivers, the main component of which was a receiver that the company had developed for field-strength measurements in civil applications. It covered 90 to 470 MHz and later was extended to 800 MHz. To fulfill such a large order, production in small quantities was out of the question, so the company made the transition from lab to factory and Messgertebau GmbH started production in Memmingen, Germany. This facility, which was enlarged in the 1960s, remains in operation today.

Reviewing Some of R&S's Many Milestones

Technical achievements at Rohde & Schwarz have been marked by many new instruments and measurement capabilities over the firm's 75 years, from relatively low reference frequencies through millimeterwave bands. For example, the company's Zg diagraph from 1950 was the industry's first commercial vector network analyzer (VNA) and the first instrument capable of displaying the magnitude and phase of scattering (S) parameters. The first model operated to 300 MHz and was later extended to 2.4 GHz.

The SWOB wideband sweep generator, also from the 1950's, automatically displayed the frequency dependencies of measured values, with considerably greater accuracy than otherwise available at the time. In 1970, the company introduced the first field-effect-transistor (FET) based root-mean-square (RMS) detector using a passive bridge circuit, eliminating the need for thermal converters (which were slow and limited in dynamic range). In 1982, Rohde & Schwarz unveiled the world's first swept frequency synthesizer, the SWP, with a frequency range of 400 kHz to 2.5 GHz. It would add the FSA spectrum analyzer in 1986, and an 18-GHz version of the SWP in 1988. More recently, the company's ZVT8 VNA launched in 2005 was the industry's first eight-port, 8-GHz VNA. In 2007, the SMF signal generator extended frequency coverage to 43.5 GHz with extremely low phase noise.

After World War II, Rohde & Schwarz received an order from the United States Army to check, calibrate, and repair radio systems. The order presented both opportunities and obstacles. Like the rest of German industry, the company was handicapped in its initial work because the Allies did not permit research, development, and production of hardware operating above 300 MHz. Rohde & Schwarz adapted its product portfolio to meet this restriction, building telephone amplifiers, cinema amplifiers, sound systems for theater stages, and even dance hall lighting.

Telecommunications presented new business opportunities for Rohde & Schwarz because an international conference had reallocated the medium-wave frequencies and Germany's assignments were not favorable. VHF FM technology offered an attractive alternative and after only four months of development, Rohde & Schwarz introduced a 250-W UHF FM transmitter that went on the air in 1949 and was the first of its kind in Europe.

The company's growth increased dramatically after the war, part of the German "Wirtschaftswunder" (Economic Miracle), with annual gains as great as 50 percent and a complementary increase in number of employees and manufacturing facilities. In 1954, the company had 1000 employees, which increased to 2000 by 1960 and 3000 by 1970. Production capacity expanded continuously in the test and measurement factory at Memmingen, a new facility in Munich, and a service center in Cologne. A large order from the Posts and Telecommunications Administration of the Federal Republic of Germany in 1969 led to construction of the Teisnach factory in the Bavarian Forest to handle prefabrication activities.

The company's product line expanded from RF measurement equipment to radio transmitters for sound broadcasting and television as well as special measurement systems for broadcasting. The field of radiolocation and monitoring was greatly expanded in the early 1950s, and Rohde & Schwarz increased its presence in radio communications equipment, ranging from shortwave to UHF as well as in measurement equipment for private mobile radio.

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In the 1950s, the company's customers were primarily the German government, including the Postal and Telecommunications Administration, armed forces, and broadcasters. Specifications for government equipment were highly customized, which was a great opportunity for Rohde & Schwarz but limited the products' utility for use by other customers. However, as the 1960s ended Germany's economic growth had slowed, prices in the electronics industry were dropping, raw materials and production costs were increasing, and the government was spending less.

This called for a new strategy, and it was delivered by Dr. Hermann Schwarz' son Friedrich, whose experience in international markets convinced him that Rohde & Schwarz should develop instruments that could be sold globally. Friedrich Schwarz was named to the executive board, and was able to persuade the company founders to pursue this strategy, which resulted in corporate restructuring into market segments and a concentration on increasing sales in other countries. The initial focus was, sensibly enough, on Europe. Representatives who for many years had been acting on behalf of Rohde & Schwarz in other countries were now more closely integrated into the corporate structure, and by 1982 international sales passed domestic sales for the first time.

To maintain this level of success, two factors had to be considered. First, the electronics industry in Europe was consolidating, which was a drastic change from the status quo, since every country typically had at least one instrument manufacturer that handled its own development and serviced its own domestic market. Only small numbers of instruments could be sold in such small markets, so prices were high. The groundswell to open up national markets in the name of European unity placed manufacturers serving a single domestic market in danger, and only a few of these companies survived. Second, the rapidly expanding Japanese capital equipment industry exerted significant pressure throughout Europe as in the US.

To meet these challenges, Rohde & Schwarz concentrated on differentiating itself by delivering high-quality, precision products and making customer service a company trademark. Its network of independent representatives was replaced by satellite offices and corporate subsidiaries that allowed Rohde & Schwarz to demonstrate its commitment to long-term local cooperation with its customers. This tradition continues today, as 80 percent of the company's products are sold outside Germany through a sales and service network spanning more than 70 countries.

In addition to its many breakthroughs in microwave and RF test and measurement (Fig. 5), Rohde & Schwarz has cemented its reputation as a leader in telecommunications test equipment. For example, when the Groupe Spcial Mobile (GSM) decided in 1987 to introduce a European-wide digital mobile radio telephone network, Rohde & Schwarz was commissioned to develop a GSM system simulator. The company's dedication to radio and TV broadcasting has also made it a leader in this market, which today includes transmitters and specialized test equipment for digital broadcasting.

As Rohde & Schwarz prepares to enter its 76th year, the wireless telecommunication industry is poised for continued evolution. New networks will be launched based on WiMAX technology, newly auctioned US spectrum at 700 MHz will be opened to development, and the 3GPP's Long-Term Evolution (LTE) enhancement to the Universal Mobile Telecommunications System (UMTS) will increase data throughput by more than an order of magnitude. Test equipment will be needed for all of these new developments, with greater accuracy and speed. And, as Rohde & Schwarz has shown during its first 75 years, it is prepared to develop the test innovations needed for the next 75 years by paying close attention to customer requirements and investing in the required technologies.

Acknowledgments
The authors wish to thank the following past and present members of the Rohde & Schwarz team for their invaluable contributions to this article: Dr. Klaus Blankenburg, the late Albert Habermann, Michael Hiebel, Wilhelm Kraemer, the late Richard Leonhardt, Thomas Reichel, Bernhard Schmidt, Friedrich Schwarz, and Tilman Betz.