- News Home
17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
18 December 1997 8:00 pm
The father of FM radio was born on this day in 1890. In the 1920s, radio broadcasting used only amplitude modulation (AM), in which a signal is transmitted by variations in the amplitude of a radio wave. Such signals were susceptible to the crackle of static from storms and electrical disturbances. In 1933, electronics engineer Edwin Armstrong introduced radio broadcasting by frequency modulation (FM), in which the signal is transmitted by variations in the frequency of the radio wave over a wide waveband. This method, which now dominates radio, television, microwave, and satellite transmissions, is unaffected by static, although it is limited to line-of-sight distances. Armstrong is also known for his invention of the superheterodyne receiving circuit, which was used during World War I to detect enemy aircraft by the radio waves given off by the ignition systems of their engines.
[Source: Roy Porter, Ed. The Biographical Dictionary of Scientists, Second Edition. Oxford University Press. 1994.]