Converting Analog to Digital

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GENERAL
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Signals in the real world are analog: light, sound, etc. Real-world signals must be converted into digital, using a circuit called ADC (Analog-to-Digital Converter), before they can be manipulated by digital equipment.

When you scan a picture with a scanner what the scanner is doing is an analog-to-digital conversion: it is taking the analog information provided by the picture (light) and converting into digital.

When you record your voice or use a VoIP solution on your computer, you are using an analog-to-digital converter to convert your voice, which is analog, into digital information.

Digital information isn't only restricted to computers. When you talk on the phone, for example, your voice is converted into digital (at the central office switch, if you use an analog line, or at you home, if you use a digital line like ISDN or DSL), since your voice is analog and the communication between the phone switches is done digitally.

When an audio CD is recorded at a studio, once again analog-to-digital is taking place, converting sounds into digital numbers that will be stored on the disc.

Whenever we need the analog signal back, the opposite conversion - digital-to-analog, which is done by a circuit called DAC, Digital-to-Analog Converter - is needed. When you play an audio CD, what the CD player is doing is reading digital information stored on the disc and converting it back to analog so you can hear the music. When you are talking on the phone, a digital-to-analog conversion is also taking place (at the central office switch, if you use an analog line, or at you home, if you use a digital line like ISDN or DSL), so you can hear what the other party is saying.

ISSUES
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1. SAMPLING RATE AND STORAGE SPACE
The more sampling points we use - i.e. the higher the sampling rate -, the more perfect will be the analog signal produced by the digital-to-analog converter.

The more samples we capture more storage space is necessary to ...