ITU-T Recommendation P.830, Subjective Performance Assessment of Telephone-Band and Wideband Digital Codecs, 1996

This revised Recommendation describes methods and procedures for conducting subjective performance evaluations of digital speech codecs. Revisions encompassed by this version of the Recommendation are to include new information that reflects current practices in subjective evaluation of digital codecs, including an expanded section on creating source recordings and addition of two annexes. One annex describes an implementation of a PCM codec (A-/u-law) that generates one quantization distortion unit (qdu) of distortion to input signals. The other new annex describes the Modified IRS transmit and receive characteristics. These characteristics are recommended as the transmit and receive responses to be used in situations where the codec being tested is intended for use in fully digital circuits.