Finally, the damped wave is already a form of amplitude modulation ( AM ) and cannot be further modulated for voice with any intelligibility.
12.
By the 1890s it was realized that damped waves had disadvantages; their energy was spread over a broad frequency modulated with an audio signal to transmit sound.
13.
When these damped waves were received by a simple detector, the operator would hear an audible buzzing sound that he could transcribe back into alpha-numeric characters.
14.
The radio signal from a spark gap transmitter consisted of pulses of radio waves ( damped waves ) which repeated at an audio rate, around several hundred per second.
15.
The classical dissipative acoustic wave propagation equations are confined to the frequency-independent and frequency-squared dependent attenuation, such as damped wave equation and approximate thermoviscous wave equation.
16.
The Morse code signal of the spark transmitter consisted of pulses of radio waves called damped waves which repeated at an audio rate, so they were audible as a buzz or tone in a receiver's earphones.
17.
After radio waves were discovered in 1887, the first generation of radio transmitter, the spark gap transmitters, produced strings of " damped waves ", pulses of radio waves which died out to zero quickly.
18.
These waves are called " damped waves " because the wave tends to " die out " or " dampen out " between discharges of the spark gap as opposed to modern continuous waves ( CW ), which don't die out.
19.
The first radio transmitter, the spark-gap transmitter, produced a string of damped waves that sounded like a buzz or tone in a radio receiver, so the pulses of radio waves used to transmit Morse code were audible as " beeps " in the receiver.
20.
There is an inverse relation between the rate of decay ( the time constant ) of a damped wave and its bandwidth; the longer the damped waves take to decay toward zero, the narrower the frequency band the radio signal occupies, so the less it interferes with other transmissions.
