Although Goodyear welted shoes are synonymous with English made footwear, the name and machinery used was in fact the invention of an American by the name of Charles Goodyear Jr, son of the great inventor Charles Goodyear, who invented vulcanised rubber.
What does AM and PM stand for? AMâalso spelled âamâ or âa.m.ââis the abbreviation for ante meridiem, a Latin phrase meaning âbefore noon.â PMâalso spelled âpmâ or âp.m.ââis the abbreviation for post meridiem, which simply means âafter noon.â Noon, of course, refers to the middle of the day.
AM stands for amplitude modulation, which means the amplitude of the radio signal is used to encode information. FM denotes frequency modulation, which uses a change in frequency to encode information. From this you can see that both AM and FM radio use modulation to encode information. Modulation is the variation of some property of the radio carrier in a manner that conveys information [1].