久久精品aⅴ无码中文字字幕重口,蜜桃久久久电影,欧美最猛,日韩天天射

Bruel & Kjaer Mouth Simulator Type 4227 is an accurate reference sound source developed for near field testing of bephone transmitters and microphones. It provides a standardised and realistic simulation of the human voice field. Features Conbs to IEEE-269, IEEE-661 and ITU-T P.51. Accurate level and frequency response calibration is easily done using a Brⁿel & Kjµr ╜ microphone placed in the supplied calibration jig Accurate simulation of human voice field Quality control testing of frequency response and distortion of bephone transmitters and close-talking microphones Continuous SPL of 100dB 25mm from lip ring Low distortion Built-in overload protection circuit