Erstellt von vincent delos reyes
vor etwa 8 Jahre
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Frage | Antworten |
romans establish postal services | 0014 |
first printing press | Johann gutenburg -1448 |
First daily news paper | 1650-leipzig |
recieves first patent for typewriter | henry mill 1714 |
invents morse code | samuel morse 1835 |
invents the first long distance electric telegraph line | samuel morse 1843 |
patents the electric telephone | alexander graham bell w/ thomas e watson - march 10 1876 |
invented the first telephone | antonio meucci and alicia gray 1843 |
patents the first fax machine | alexander bain 1843 |
patents the direct dial telephone/automatic telephone exchange | almon b strowger 1889 |
first words from the telephone | watson come here i want you |
improves wireless telegraphy | guglielmo marconi 1894 |
-transmits radio signals from cornwall to newfoundland -first radio signal across atlantic ocean | guglielmo marconi 1902 |
electronic amplifying tube or triode | lee deforest 1906 |
am radio broadcasting | 1920 |
-television or iconoscope (cathode ray tube) -first television camera | vladimir kosma zworykin -1923 |
radio astronomy discovered | 1931 |
FM radio | Maj. edwin howard armstrong -1933 |
RADAR and SONAR perfected | 1940 |
inevented transistor | -william shockley, walter brattain, john bardeen dec 23 1947 |
cable tv (community antenna) first appears | 1950 |
computers are first solf commercially | 1951 |
Integrated circuit | jack kilby 1960 |
introduction to first communication satellite | 1962 |
the first internet started | ARPANET 1969 |
floppy disk invented | 1971 |
first cellular phone comm network started in japan | 1979 |
-IBM PC first sold -first laptop computers sold to public | 1981 |
IBM PC AT released | 1984 |
GPS used commercial and personal applications | 1989 |
Am govt releases controll of internet and www is born - making comm at light speed | 1994 |
30-300Hz | extremely low f |
300-3000Hz | super low f |
3-30khz | very low f |
30-300khz | low f |
300-3000khz | medium f |
3-30mhz | high f |
30-300mhz | very high f |
300-3000mhz | ultra high f |
3-30ghz | super high f |
30-300ghz | extremely high f |
300-3000ghz | infrared light |
3-30thz | infrared light |
30-300thz | infrared light |
300-3000thz | visible light |
3-30Phz | ultra violet light |
30-300phz | xrays |
300-3000phz | gamma rays |
3-30Ehz | cosmic rays |
basic process of exchanging info | communication |
basic components of electronic communication | -transmitter -channel or medium -receiver |
unwanted signal produced by atmsphre | noise |
to convert the info into a suitablr signal over a medium | transmitter |
to convert the sgnal back to original info | reciever |
the medium by which the electronic signal is transmitted from 1 place to another | comm channel |
two types of comm | -wire / line -wireless /radio |
continiously varying signsal | analog |
has only two distinct levels high and low | digital |
transmission of orig signal wo modulation | basband transmission |
portion of frequency range occupied by th signal | bandwidth |
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