The needle of the speed-indicator flicked and wagged to and fro; the cinders rattled on the roof, and a whirl of dust sucked after the whirling wheels, The crew of the combination sat on their bunks, panting in their shirt- sleeves, and Cheyne found himself among them shouting old, old stories of the railroad that every trainman knows, above the ...
One of the main drawbacks to a digital TV signal or digital cable signal, for instance, is that it is an artificial reproduction of the original data, whereas an analog signal starts out as an exact copy of the original.
Waves are a wiggle in space cause by a vibration or disturbance. They have the ability to carry energy from one location to another. There are two different types of waves; transverse and longitudinal. A transverse wave is when the wave is vibrating perpendicular to the direction the wave is traveling. A longitudinal wave, also called a compression wave, is a wave in which the vibration is in the same direction as that in which the wave is traveling. How frequently a wave or vibration occurs during a span of time, determines the waves frequency. Frequency is the number of waves per unit time.