Nexus - 1604 - New Times Magazine-pages

Page Content (OCR)

NEWSCIENCENEWSCIENCENEWSCIENCE reaches them, greatly amplified, through public-address loud speakers. The secret is a tiny microphone, no larger than a quarter, hidden in the breast pocket of my coat and connected to a trailing wire passing down to the floor inside my clothing. Originally a development of an improved transmitter for [a] telephone operator, the device is now serving in a totally different field. oceanic radio telephone system. With a long coil spring connected to a telephone transmitter at one side of the stage, it is possible to so delay the movement of the voice vibrations along the wire that you can speak in one end and hear the words come out the other quite a bit later. That's more or less a mechanical affair, the shape of the coiled spring actually delaying the movement of the waves. But down in lower New York, every message passing through on the the relays, being mechanical, must have a fraction of a second to work. That's where the speech-delay apparatus comes in. The man in London may start talking instantly, but the apparatus will store up his voice in London for an instant while the relays are doing their work. transmitter for [a] telephone mechanical affair, the shape of the Improving sound reproduction operator, the device is now serving coiled spring actually delaying the While primarily concerned with in a totally different field. movement of the waves. the development of the telephone, But down in lower New York, every we are constantly contributing to Foiling bank robbers message passing through on the’ many other fields. One of the most Another use for small and recent developments was the extremely sensitive eliminating of the last microphones is in guarding the disturbing sound from talking- vaults of the Federal Reserve . picture films. In the early days and many other banks. Tiny We have found that the light of sound recording on movie microphones are set in the not only talks but that it is ilm, there were many outside vault walls, and they are so modulated by the voice current, noises. Eventually they were sensitive that a hand tipping A i eliminated one by one, unti against the vault will set them Just as the glow of a neon lamp Is inally only a swishing sound off, while they are so adjusted | modulated by the signals reaching ff remained. By changing the that they remain insensitive to a television receiver. mechanism of the light valve footsteps passing near, to at the recording end it is now trucks in the street and to the possible to eliminate this las rumbling subway trains. noise, and a remarkable A very clever electrical change in talking pictures was engineer might possibly locate one he result. of the circuits and, after study, radio telephone circuits is delayed Research in the recording o determine just the right amount of for a couple of hundredths of a_ talking-picture sounds on wax discs resistance to put into the line and second by electrical means. The also has resulted in a marked so circumvent the microphones trans-Atlantic wireless-telephone improvement in reproduction. We while bank robbers could work. So, service can work in only one have gone back to Edison's origina to guard against that bare chance, direction at a time, because the method, as used on the old-time the watch service officers are sending and receiving stations are cylinder records. He utilized what is provided with a device by which, at tuned to the same wave-length. A known as “hill and dale" recording, frequent intervals, they can sweep voice current going to Europe is the cutting stylus engraving a line o through a whole cycle of resistance picked up also by the American varying depth, instead of the waving, changes and determine whether receiver, and, unless the wire line side-to-side method which Berliner anyone has been tampering with the between the receiver and transmitter developed with the first disc circuit. The cleverest bank robber is blocked, the signal would "loop records. The hill-and-dale method doesn't have a chance with this the loop", causing the circuit to was not a success because of the system. owl. If you are talking from New limitations of the acoustical method York to London, you control the of recording. Speech-delay mechanism circuit so long as your voice In following the wavy line on Another laboratory experiment continues. When you stop, relays present-day records, e which always fascinates the public is must work to reverse the channel so reproducing needle is thrown back the speech-delay mechanism, which, the person at the other end can and forth from side to side of the in one form, is just a clever answer. groove, and does not follow amusement device and, in another, Your voice, as electrical impulses, accurately the path traced by the is an important part of the trans- travels with the speed of light, while cutting stylus. By reverting to the We have found that the light not only talks but that it is modulated by the voice current, just as the glow of a neon lamp is modulated by the signals reaching a television receiver. radio telephone circuits is delayed for a couple of hundredths of a second by electrical means. The trans-Atlantic wireless-telephone service can work in only one direction at a time, because the sending and receiving stations are tuned to the same wave-length. A voice current going to Europe is picked up also by the American receiver, and, unless the wire line between the receiver and transmitter is blocked, the signal would "loop the loop", causing the circuit to howl. If you are talking from New York to London, you control the circuit so long as your voice continues. When you stop, relays must work to reverse the channel so the person at the other end can answer. system. Speech-delay mechanism Another laboratory experiment which always fascinates the public is the speech-delay mechanism, which, in one form, is just a clever amusement device and, in another, is an important part of the trans- Your voice, as electrical impulses, travels with the speed of light, while JUNE — JULY 2009 NEXUS ¢ 53 www.nexusmagazine.com