See Also: Digital , Digital-To-Analog Conversion
Analog refers to data that can have any negative or positive value.
Analog Signal
Everything that we see and hear reaches us through analog Waves. When we speak, we produce analog waves. When we hear a Sound, we receive and process analog signals. An analog signal is a smooth and
continuous wave.
Modern Telephone networks no longer use analog signaling to transmit calls. As signals are
transmitted, they grow weaker as the distance increases and become distorted with
extraneous Noise (see Pulse Amplitude Modulation). In order to extend the reach of analog signals thousands of miles, the
electrical (see Electricity) signal must be amplified (see Amplifier). Unfortunately, amplifiers cannot distinguish between the voice portion of
the signal and the extraneous noise introduced during transmission. While the
distortions introduced in transmission are acceptable for normal conversations,
the small errors in the electrical signal will not be heard by the listener.
However, when the network is used for the transmission of data, accuracy
becomes a primary consideration. A single undetected error in the data could change
its entire meaning. For example, erroneously dropping or changing a digit in a
financial transaction could have severe consequences. Because of the need for
error-free transmission and to improve overall efficiencies, digital
transmission is now used for virtually all long-distance transactions.