diffrence between digital signal and analoge signal?

Answer 1

An analog signal is a continuous wave form, also called a sine wave. Natural sound is an analog waveform.

Digital signals are distinct on and off pulses that form a square shaped wave form.

Analog signals sampled at least two times per cycle and the amplitude of the sample is converted to a digital equivalent. This analog to digital conversion technique is called Pulse Amplitude Modulation (PAM).

PAM is then converted to Pulse Code Modulation (PCM). PCM is the basic audio digital signal. Nearly all other common digital audio signals are derived from PCM, including mp3, AAC, AMR, etc...

Analog signals which are more complex than audio use similar techniques for conversion to digital signal. Special computer processors are designed specifically to convert Analog to Digital (ADC) and Digital to Analog (DAC).

Once an analog signal is converted to digital, very powerful processors are used to manipulate the signal. These are called Digital Signal Processors (DSP). If you have a Home Theater system that supports different sound stages like a Music Hall, or a Rock Concert, or THX, these are DSPs manipulating the digital audio signals.

Answer 2

http://en.wikipedia.org/wiki/Analog_vs._Digital