How Digital Signals Work
Digital signals consist of a large stream of numbers which gives them their name, these numbers fluctuate between 1 and 0 and is normally called a binary system or data stream. This gives them only two possible options either number 1 or 0. To explain better how these signals work, we can compare them with a light switch that can be only be used in the on or off position leaving no room for a dimmer light setting. Another example that is commonly used, is a comparison between a digital clock where you can only see the exact minute change and an analog clock where there is movement in the clock's hand between minutes.
When decoded, they issue a command that in this case, indicates how the television sets pixels light up to produce the image and how sound frequencies are constructed including their amplitude (volume within the sound mix). The sole fact that this technology uses only a binary stream of numbers is what makes them less prone to interference. This is possible because interference that tries to enter the stream of data and that is not encoded in this format is immediately discarded reducing the probability that the interference manifests itself in a continuous fashion. In other words signals that do not belong to the binary stream of data is considered noise and ignored.
What This Means for Satellite And Cable Tv Services
Digital television looks sharper and more defined. In the case that data is corrupted the image usually breaks into squared segments in the way that commonly happens when there are signal problems when using services such as Direct TV, Dish Network or any Digital cable service. In fact, if you have used one of these services under poor signal circumstances like a very bad weather, you have a real example of how a poor DTV signal would behave when reception is not good.
Analog Signals And The Consistent Interference Problem
An analog signal functions in a very different way than a digital one. If we go back to the example above that compares digital signals with an off light switch, an analog signal can be compared with a light dimmer where turning it only half way still gives a dim light and is not limited to only an on and off position. To put it simple, every position in the transmitted wave is counted and gives different results. This is an example of how analog works, as a continuous wave with varying intensities. This information is converted by the television set and displayed as colors in its individual pixels forming image and sound.
An analog signal is more prone to interference. The very nature of the waves themselves is to blame. The very fact that different points inside a wave are considered by the receiving device makes room for a lot of signal noise to enter it causing undesired effects. With very little way for an analog television set to be able to tell if what is received is is part of the broadcast or not gives room constant interference.
We are all aware of how easily interference can enter an analog signal when even a passing car or a citizen band radio can easily cause an noticeable effect on audio and video especially when the strength of the reception is poor. These can manifest like double images usually known as ghosts, audio that gets substituted by other unwanted sounds, rainy, discolored or heavily scrambled images not to mention strange colored bands that move through out the screen.
After establishing the difference between analog and digital signals we can then conclude that digital television known as DTV is a better broadcasting technology than older, more unreliable analog technology.