Marcel Bayard (1895-1956) was a French mathematician and telecommunications engineer. He made pioneering contributions to the telecommunications theory in the 1930s. As Chief Engineer of French telecommunications after World War II, he supervised and modernized the French telecommunications system.

Biography

Born in 1895, son of a farmer, he obtained his

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in 1914. He served as young officer during the World War I where he was seriously wounded and received the

Croix de Guerre The ''Croix de Guerre'' (, ''Cross of War'') is a military decoration of France. It was first created in 1915 and consists of a square-cross medal on two crossed swords, hanging from a ribbon with various degree pins. The decoration was first awa ...

. He entered the

École polytechnique École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine The Seine ( , ) is a river in northern Franc ...

in 1919. In 1923 he became an engineer in the French PTT and started his career by supervising submarine cable installations. As professor at the ''École nationale supérieure des télécommunications'', he published several noted scientific papers. He was the first to establish in 1935 what is called the “Bayard- Bode relations” (relations linking Phase and

Amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of a ...

of a signal in specific cases. He also wrote the theorical electricity lessons for the École nationale supérieure des télécommunications where he was the first in France to introduce the

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calculations for

electrical network An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sour ...

theory. He represented France in international telecommunications committees in the 1930s. After World War II, he was responsible for rebuilding and modernizing the French telecommunications network.

Membership & Honors

* Director of studies of the École nationale supérieure des télécommunications in 1941 * Chief Engineer of French Telecommunications in 1954. * He was elected in 1950 vice-president of the

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Legacy

*The French cable layer Marcel Bayard ( :fr:Marcel Bayard (câblier)) named after him was launched in 1961.

References

Sources Les pionniers de la téléphonie sous-marin

Publications

* ''Sur la propagation des ondes le long des lignes de transmission et sur le calcul de l'onde résultante après les réflexions successives aux extrémités'', bulletin de la Société française des électriciens N°23, March 1943. * ''Cours d'électricité théorique'', cours à l'École Nationale des Télécommunications, 1945 & 1948. * ''Théorie des réseaux de Kirchhoff-Régime sinusoïdal et synthèse'', collection technique et scientifique du CNET, 1954 {{DEFAULTSORT:Bayard, Marcel 1895 births 1956 deaths People from Haute-Loire 20th-century French mathematicians French telecommunications engineers French electrical engineers École Polytechnique alumni Télécom Paris alumni Supélec alumni