Audio Codec Article Index for
Audio
Website Links For
Audio
 

Information About

Audio Codec




In some contexts, the term "audio codec" can refer to a hardware implementation or Sound Card . When used in this manner, the phrase ''audio codec'' refers to the device encoding an analog audio signal to a digital audio signal, or decoding an analog audio signal from a digital audio signal. Thus, in such a context, the term is actually referring to a combined audio AD/DA converter. One example is Intel Corporation 's AC'97 standard, which comprises a digital controller paired with an analog unit.

The use of digital samples to represent audio data is subject to some fundamental limitations regardless of the codec. The Bandwidth is limited by the Nyquist–Shannon Sampling Theorem so that the highest audio Frequency that can be reconstructed from the digital data is half the sample frequency. The Dynamic Range is limited by Quantization Noise which is half the weight of the least significant bit of each sample. A perfect linear codec (which is considered ''lossless'') will suffer these types of signal degradation but nothing else. Codecs which are considered ''lossy'' will suffer the same fundamental types of signal degradation plus some additional lost signal which varies from codec to codec.


SEE ALSO