Communication theory and physics
- 1 February 1953
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in Transactions of the IRE Professional Group on Information Theory
- Vol. 1 (1), 48-59
- https://doi.org/10.1109/tit.1953.1188558
Abstract
The electromagnetic signals used in communication are subject to the general laws of radiation. One obtains a complete representation of a signal by dividing the time-frequency plane into cells of unit area and associating with every cell a "ladder" of distinguishable steps in signal intensity. The steps are determined by Einstein's law of energy fluctuation, involving both waves and photons. This representation, however, gives only one datum per cell, viz. the energy, while in the classical description one has two data; an amplitude and a phase. It is shown in the second part of the paper that both descriptions are practically equivalent in the long-wave region, or for strong signals, as they contain approximately the same number of independent, distinguishable data, but the classical description is always a little less complete than the quantum description. In the best possible experimental analysis the number of distinguishable steps in the measurement of amplitude and phase is only the fourth root of the number of photons. Thus it takes a hundred million photons per cell in order to define amplitude and phase to one percent each.Keywords
This publication has 8 references indexed in Scilit:
- XXIV. Quantal aspects of scientific informationJournal of Computers in Education, 1950
- CIII. Communication theory and physicsJournal of Computers in Education, 1950
- Theoretical Limitations on the Rate of Transmission of InformationProceedings of the IRE, 1949
- Acoustical Quanta and the Theory of HearingNature, 1947
- Quantum Effects in the Interaction of Electrons With High Frequency Fields and the Transition to Classical TheoryPhysical Review B, 1946
- ber die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter WesenThe European Physical Journal A, 1929
- Thermal Agitation of Electric Charge in ConductorsPhysical Review B, 1928
- Über die Ausdehnung der phänomenologischen Thermodynamik auf die SchwankungserscheinungenThe European Physical Journal A, 1925