A sound card is essentially an interface device for capturing the audio and interfacing it with different audio controls. The sound card initially was of 8-bits but now most of the sound cards are 16 bits. A sound card may also be referred as audio card which will be attached with ISA or PCI slots of a mother board. It enables the Computer to input, process and deliver the sound.
Main functions of a sound card are as follows:
1. To provide an interface for audio input and output.
2. To provide a MIDI interface.
3. Analog to digital conversion. Digital to Analog conversion.
Analog versus Digital Sound:
In analog, physical sound pressure waves are converted to corresponding electrical signals by an acoustic transducer such as microphone or phonograph cartridge. The electrical output of transducer is called an analog signal because electrical signal is analogous to (representative) of the pressure pattern of sound wave that created it. Sound signals are most often represented in the form of two dimensional wave pattern whose y-axis is the intensity or amplitude of the signal and whose x-axis represents the passage of time.
Analog to Digital Converter (ADC) are used to measure the analog signal and express instantaneous values of signals amplitude in digital form.
In digital audio, the sound is a repeated pattern of pressure in the air and a microphone converts a sound wave into an electric wave. The shape and frequency of the electric wave is identical to the shape and frequency of the sound wave and clarity of what we hear is entirely dependent on the shape of frequency of sound. Audio has to be converted into digital form to produce digital audio in order to use it in multimedia. And the digital audio system will then reconvert the entire digitized audio into analog form, which can be heard on speaker. Storage space required for digital audio is huge then analog audio.
In multimedia it is more advisable to keep all audio in digital format then in audio format.
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