A doctor’s son in Bergamo
Andrea Giacomo Viterbi was born on March 9, 1935, in Bergamo, in northern Italy, into an Italian Jewish family. His father, Achille Viterbi, had won the competition to head the ophthalmology department of Bergamo’s hospital; his mother, Maria Luria Viterbi, came from a family of bankers in Casale Monferrato in Piedmont. They lived a comfortable middle-class life, with household help, in a city whose Jewish community numbered only some sixty or seventy people.
The family were patriotic Italians and, as Viterbi later put it, certainly not enthusiasts for Fascism. In 1938 Mussolini’s government introduced its racial laws, which stripped Jews of public employment, and Achille Viterbi lost his hospital post because he was a Jew. His father afterwards referred to the laws simply as la batosta, the blow.
Escape to America
In January 1939 the family sold their belongings in haste and moved to Genoa while Achille sought visas for the United States in Naples. He obtained one for himself and, through acquaintances, found a way to secure visas for his wife and son. The Viterbis had booked passage on the liner Normandie for early September, but rumours of imminent German action led them to sail instead on the De Grasse on August 15, 1939. They reached New York on August 27, days before Germany invaded Poland. The Normandie never made its scheduled sailing.
Andrea became Andrew. After two years in New York the family settled in Boston in 1941. His father, in his late fifties, had to study again for an American medical license because his Italian degree was not recognised, and he built a small practice serving Italian immigrants in the North End. After Pearl Harbor the family were treated as enemy aliens and fingerprinted. Achille liked to say that to the Italians they were Jews and to the Jews they were Italians.
The schools of Boston would not at first admit Andrew to second grade because he was an immigrant, which made his father furious; his parents taught him at home until he could skip ahead. The FBI confiscated his father’s camera after the United States entered the war, and when Achille later went to collect it and it was returned, he exclaimed “Only in America!” The family’s social circle was a group of about ten Italian Jewish refugee families, most of whom returned to Italy after the war; the Viterbis stayed. Most of their relatives in Italy survived the war in hiding, though one distant cousin was deported.
Boston Latin, MIT and the space age
Andrew attended Boston Latin School, graduating in 1952, and entered the Massachusetts Institute of Technology to study electrical engineering, earning both bachelor’s and master’s degrees in 1957. That year he moved to California to join the Jet Propulsion Laboratory in Pasadena, where he worked on telemetry, the radio links that carry measurements back from rockets and satellites, including work connected to Explorer 1, the first American satellite. He also helped develop the phase-locked loop, a circuit used to lock on to faint radio signals.
While working at JPL he studied part-time at the University of Southern California, receiving one of its early doctorates in electrical engineering in 1962, with a dissertation on digital communications. He then joined the faculty of the University of California, Los Angeles, and later taught at the University of California, San Diego.
The Viterbi algorithm
Every digital message sent by radio arrives damaged. Noise, interference and fading flip some of the ones and zeros. Engineers protect messages by adding carefully structured redundancy, known as error-correcting codes. One powerful family, convolutional codes, spreads each bit of information across many transmitted bits. The difficulty was decoding them: checking every possible original message against what was received quickly becomes impossible.
In 1966, while teaching at UCLA, Viterbi devised a method, published in 1967, that solved the problem with remarkable economy. At each step, his algorithm keeps track only of the most likely path that could have led to each possible state of the encoder, and discards all the others, so that the work grows only modestly with the length of the message. It was later shown to find the single most likely transmitted message. On a lawyer’s advice, Viterbi did not patent it, and it spread freely.
The Viterbi algorithm became one of the most widely used algorithms in engineering. It decodes signals in deep-space communications, satellite television receivers and digital radio, and it has been used in all the main digital cellular phone standards. Because it finds the most likely sequence of hidden states behind noisy observations, it is also used in speech recognition, in the analysis of DNA sequences and in many other applications of what statisticians call hidden Markov models.
Linkabit, Qualcomm and CDMA
With his fellow engineer Irwin Jacobs, Viterbi co-founded Linkabit Corporation in 1968, a small company that grew into a leading supplier of satellite communications technology, much of it for defence. In 1985 Jacobs and Viterbi founded a new company in San Diego: Qualcomm.
Qualcomm championed Code Division Multiple Access, or CDMA, a way for many mobile phones to share the same radio frequencies at once, each signal spread out with its own code. Drawing on spread-spectrum techniques he had studied since his JPL days, Viterbi helped develop the theory and the standard. CDMA offered far greater capacity than earlier analogue systems; by his own calculations, ten to twenty times more. Its principles were carried into third-generation mobile networks, which brought mobile internet to billions of people. The IEEE later recognised CDMA and spread-spectrum work by Jacobs and Viterbi with a Milestone award in 2017. Viterbi stepped down as Qualcomm’s vice chairman and chief technical officer in 2000.
CDMA was controversial at first. Many in the industry doubted that it could work in crowded cities, where signals from phones near a tower can drown out those far away. Qualcomm’s engineers, drawing on Viterbi’s analysis, solved such problems with precise control of each phone’s transmitting power and other techniques, and CDMA networks were launched commercially in the mid-1990s. By 2000 about 50 million CDMA phones were in use around the world, and Viterbi later described the work as a team effort of which he was proud to have been part.
Giving back
In 2004 Andrew and Erna Viterbi gave 52 million dollars to the University of Southern California, at the time the largest gift ever made to name an engineering school; it became the USC Viterbi School of Engineering. They had earlier endowed a chair in communications there, and in 2002 Viterbi dedicated a computer centre at his old school, Boston Latin. He has served on the boards of USC and the Scripps Research Institute and supported the Technion in Israel, whose electrical and computer engineering faculty also carries the Viterbi name.
His honours include the IEEE Alexander Graham Bell Medal (1984), the Marconi Prize (1990), the Claude E. Shannon Award (1991), the U.S. National Medal of Science, the Millennium Technology Prize (2008) and the IEEE Medal of Honor (2010). He is one of the few people elected to both the National Academy of Engineering and the National Academy of Sciences.
Jewish identity and family
The Viterbis were not a religious family. In Boston a family friend arranged membership at Temple Ohabei Shalom in Brookline, where Andrew received some Jewish education, and he had his bar mitzvah in Turin in 1948, on a visit to relatives in Italy. He has said he felt part of the Jewish community, if unofficially. Through his family he was connected to the writer Primo Levi, an Auschwitz survivor: his aunt in Turin was Levi’s mother-in-law.
He married Erna Finci, herself a Jewish refugee and Holocaust survivor. Her family fled Sarajevo in 1941, were interned by the Italians near Parma, were sheltered by villagers after 1943 and escaped across the Alps to Switzerland. The couple had three children, Alan, Audrey and Alexander; Alexander died in 2011. Erna died in 2015. Viterbi has spoken publicly about his family’s flight, including in a recorded interview with the Primo Levi Center in New York, noting that Italy never apologised to his father.
Erna’s family history mirrored his own in reverse. Italy had turned its back on his family, but for hers, fleeing the Nazis and their allies in Yugoslavia, Italian-occupied territory and Italian villagers offered a refuge; after the September 1943 armistice, local people helped them escape to Switzerland. Viterbi has reflected that, compared with much of Europe, Italians were relatively kind, but that most stood by while the racial laws were enforced, and that loyal, patriotic Italian Jews felt the betrayal all the more keenly.
Legacy
Andrew Viterbi’s algorithm is one of the invisible workhorses of the digital age, running quietly inside phones, modems, satellite receivers and spacecraft, and his work on CDMA helped turn the mobile phone from a luxury into something carried by billions of people. Because he left the algorithm unpatented, engineers everywhere could build on it freely.
His life also traces one of the twentieth century’s great journeys: a four-year-old boy whose family was pushed out of Fascist Italy by racial laws became one of the engineers who connected the world. The school that bears his and his wife’s name trains thousands of engineers each year.
Sources & further reading
Andrew Viterbi, Wikipedia · About Andrew J. Viterbi, USC Viterbi School of Engineering · One Family, Two Diverging Experiences in Fascist Italy, Primo Levi Center · Jewish Computer and Information Scientists, jinfo.org · Researched from the sources above and checked against them. Spotted an error? Tell us.
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