Evaluating Psychoacoustic Parameters and Quality of Transmitted Speech Over Wireless Networks

Psychoacoustic parameter of sound known as loudness is a major quality factor for assessing the perceptual quality of service of speech signals transmitted through telecommunication networks. The Zwicker and Fastl loudness model is a preferred loudness model and in this work has been programmed to obtain both loudness and loudness level of speeches transmitted over wireless. Here,the best maximum instantaneous loudness of the transmitted speeches is 42.55% of that of the original speech. While the best maximum instantaneous loudness level of the transmitted speeches is 87.06% of that of the original speech. These showed an intuitive and innovative representation of the degradation suffered by the transmitted speeches with respect to the original speech.

Identification of Pick Up Noise for Laser Printers Based on Psychoacoustic Parameters

This paper illustrates that a method for identification of pick up noise and an analysis the cause of pick up noise by substituting components of a laser printer. The operating sound radiated from a laser printer includes the tonal noise components caused by the rotating mechanical components such as gear, shaft, motor, fan, etc. A sound operated by laser printers has become important competitiveness in printer industries as the demand of laser printers increases. Especially, a noise between a friction pad and a paper in the process of printing has become an essential issue in an aspect of quality evaluation. However the existing criteria for determining the above noise have solely relied on human’s subjective judgments; which highlights the requirement to objectify these criteria. In this paper, the standard of existing pick up noise is established by finding the tonality, which is a psychoacoustic parameter, of noticeable limit sound level. Based on the findings of the method, the study has found factors which cause pick-up noise and suggests the substitution of following components of printers such as: spring constants, spring force, and the quality of friction pads. As a result, it is confirmed that the proposed pick up noise index has usefulness to classify whether existence of pick up noise with an objective evaluation and not to occur the noise based on design optimized combination of laser printer components.