Word: doppler
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Dates: during 1960-1969
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...Doptone, based on the Doppler effect, transmits a narrow beam of very-high-frequency sound into the abdomen, detects fetal life and heartbeat after the tenth week of gestation, with out harming the mother. It also pin points blockages in peripheral arteries, as a guide to surgery...
Einstein's prediction is also known as the gravitational red shift. This shift (the observed frequency changes in light waves) is similar to the Doppler effect for sound waves: the frequency of vibration of a light source moving toward an observer seems to increase just as the horn of an onrushing train apparently rises in pitch. To test this principle, Pound set up a source of radiation at the top of a 75-foot shaft in the Jefferson Physical Laboratory. At the bottom of the shaft was an absorber...
...noise that comes back from the bottom is changed in frequency by the movement of the ship. This easily detected frequency shift is the celebrated Doppler effect, and a computer translates the change into speed-and-direction instructions for the automatic marking pen. A single dial adjusts the navigator to the scale of any standard marine chart. And last week's sea trial found the new Doppler sonar accurate within a startling...
...Overboard. Now that his newest brainchild has proved such a prodigy, Sonar Engineer Edwin Turner, 64, plans to deliver two prototypes to the Navy for further trials and then retire. He stresses that Doppler sonar is a supplement, not a replacement for radar and other modern navigational aids. It can function properly only in well-charted waters or far at sea, where the course picked out by its pen is not likely to run into unexpected obstacles. The Navy already has a built-in need for such a device on many of its ships, and along the world...
Radar Wrinkles. The most promising newcomer among aircraft navigation instruments is Doppler radar. The name honors the 19th century Physicist Christian Doppler, who discovered that sound waves transmitted from a moving object change in frequency. This Doppler effect applies equally to radio waves...