The Communication Method of Distance Education System and Sound Control Characteristics

The present in used distance education system is based on audiovisual communications. So when a teacher gives lessons to many students who are dispersed in distant places, the teacher obtains input from students through image and sound information. The students can be visually distinguished by separately displaying an active picture and a non-active background. But it is hard to distinguish the students aurally when multiple sounds come from the same loudspeaker simultaneously. In a normal class, a teacher can usually obtain feedback from students and can respond to a question immediately. It is equally necessary to get student feedback through sound information in distance education. We examined how background sound affects the active sound in a practical distance education system, and studied how to main image interference. 2nd experiment, Next, we define the sound loudness as the sound pressure, perform AHP (Analytic Hierarchy Process) analysis for relation between the sound pressure and the sound image in this case, and elucidate the audibility characteristics. We define the time delay as the sound pressure, perform AHP analysis for relation between the time-difference and the sound image in this case, and elucidate the audibility characteristics.