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Analog transmission is the traditional method of sending and receiving telecommunications signals. These signals are sent in the form of waves, which duplicate the transmission as it was picked up at the source or input. An analog transmission is sent over a single channel. Radio, television and phone analog transmissions can be translated into digital signals with the use of certain devices that convert the wave into digital or binary format.
Before the introduction of digital receivers and devices, all radio, television and telephone signals were sent through analog transmission. In fact, most digital transmissions simply convert analog waves into binary format in order to achieve increased channel capacity. For example, much of the wireless telecommunications industry employed this concept as it made the switch from analog to digital devices. As demand for service increased, it was necessary to upgrade cell towers and switch subscribers to digital phones in order to accommodate the jump in the level of voice transmissions.
An analog transmission duplicates the sound or picture from the original source. In a voice transmission, an analog signal represents a sound wave. The replica of the sound wave is sent as electricity through a wire and then converted back into a sound wave at the receiving end. In the case of analog cable television transmissions, a replica of the picture is sent through the cable and converted back into its original form.
The main difference between analog transmission and digital is that digital operates under the binary system. Voice or picture signals are converted into numbers before they are transmitted. Under the binary system, a series of zeros and ones are used to represent and send the signals. Analog, on the other hand, simply creates an identical version of the original.
Another difference between analog and digital transmissions is that analog signals are transmitted continuously. In other words, the signals are always present over a specific range. Digital signals can be either "on" or "off" according to their binary code. Analog signals can also vary over a certain amount of time.
There tends to be more noise or interference with an analog transmission. This is because the signal waves tend to amplify sound, which means that any static or other noises that may be picked up during the transmission are also amplified. In contrast, digital transmissions tend to be more precise and accurate once they are received. The rate of errors that occur during transmission also tends to be higher with the use of analog based technology.
The problem of weak digital signals can be cleaned up a bit with a decent outdoor antenna and an amplifier. That old roof antenna that you received analog TV signals with will probably still work fine for digital signals, but some stations may need to be cleaned up with an amplifier.
Luckily, a good antenna amplifier can be had for less than $50 and those are easy to install.
A big difference between analog and digital transmissions is well known to anyone still using an antenna to pick up over the air TV signals. You could have a little garbage and noise in an analog signal and still see a picture that was fairly good. Weak signals may have meant a fuzzy picture, but one could still receive it and adjust the antenna for a result that was "good enough."
That's not the case with digital signals. A set either receives them or it doesn't. A weak signal, then, results in a black television screen.
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