The Preference of Slope Overload to Granularity in the Delta Modulation of Speech
Nikil S. Jayant, A. E. Rosenberg · The Journal of the Acoustical Society of America · 1971
A preference study was made to assess the relative annoyance values of slope-overload distortion and granular noise in delta-modulated speech. The delta modulation was performed at frequencies of 20 and 40 kHz, and controlled amounts of the two types of degradation were introduced into samples of a 2-sec utterance. Rankings were obtained for these samples on the basis of paired-comparison preference judgments of nine listeners in a tournament-type strategy. Results indicate that the speech sample exhibiting the minimum degradation on an objective over-all noise-power basis is not a subjectively optimum sample but has a greater overload-to-granularity ratio than the objectively optimum utterance.