17. 44AA Mouth Simulator

The GRAS 43AA is a complete test jig for acoustical measurements on telephone handsets and earphones in accordance with:

GRAS 43AA是一款完整的测试夹具，用于电话手机和耳机的声学测量，符合：

GRAS

- IEC60318-1 & -2 Electroacoustics – Simulators of human head and ear – Part 1: Ear simulator for     the calibration of supraaural earphones, 1998-07.  IEC60318-1＆-2电声学 - 人头部及躯干模拟器和仿真 耳 - 第1部分：用于校准耳上耳机的仿真耳，1998-07

   

- ITU-T Recommendation P.57 (08/96) Series P: Telephone transmission Quality, Objective           

   measuring apparatus: Artificial Ears.  ITU-T 建议P.57（08/96）系列P：电话传输质量，客观测量设备：仿真耳朵

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仿真耳朵

At the mouth reference point (MRP), which is 25mm from the detachable lip ring (35mm from the mouth of the G.R.A.S. 44AA), the maximum continuous signal it can produce in 1/3-octave bands is 100dB re. 20µPa in the frequency range 100Hz to 16kHz. Its loudspeaker accepts an external signal either directly or via its own built-in power amplifier (when power is applied).

在距离可拆卸唇圈25毫米(距离G.R.A.S.44AA 35mm）的嘴基准点（MRP）处 ， 在100Hz至16kHz的频率范围內可以在1/3倍频程带产生的最大连续信号为100dB re.20μPa 。它扬声器（在通电时）能直接或经由其自身的内置功率放大器接受外部信号。

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Jigs are included for calibration according to CCITT P.51 and IEEE 269. These are for use with 1/4" or 1/2" microphones. One jig holds the microphone at 0º incidence (1/4" only) to the sound source, the other at 90º incidence (1/4" or 1/2").

夹具用于根据 CCITT P.51 和 IEEE 269 进行校准。这些夹具用于 1/4寸或 1/2寸麦克风。 一个夹具将麦克风固定在 90º入射（只限1/4寸麦克风）到声源，另一个在 90º入射（1/4寸或 1/2寸）处。

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麦克风

Built-in power amplifier

Maximum continuous output level at MRP [200 Hz - 6 kHz] 110 dB re. 20 μPa

Maximum continuous output level at MRP [100 Hz - 16 kHz] 100 dB re. 20 μPa

Distortion 250 Hz - 8 kHz (Linear signal @ 94 dB at MRP) typically 1 %, max. 1.5 %

内置功率放大器

MRP [200 Hz - 6 kHz]的最大连续输出电平为 110 dB. 20μPa

MRP [100 Hz - 16 kHz]的最大连续输出电平为 100 dB re. 20μPa

失真 250 Hz - 8 kHz（MRP 时线性信号@ 94 dB）通常为 1％，最大 1.5％ 

S&V Samford Instruments Ltd. 

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